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ETS 910 manual

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ETS 910 manual Powered By Docstoc
         Model 910

     Operating Manual


                         TABLE OF CONTENTS

PARAGRAPH   DESCRIPTION                                  PAGE
1.0         INTRODUCTION                                  1

2.0         EQUIPMENT DESCRIPTION                         2
2.1         General Description                           2
2.2         Controls                                      3
2.2.1       Main AC Power ON/OFF                          3
2.2.2       High Voltage Controls                         3     High Voltage ON/OFF                           3     High Voltage HI/LO Model Select               4     High Voltage POLARITY (+/-) Select            4     High Voltage COARSE and FINE Adjust           4
2.2.3       Operating Mode Controls (LO and HI Ranges)    4     Manual Mode                                   4   Manual/Auto Mode Select                       5   DISCHARGE Control (Manual Mode)               5   HOLD Button                                   5     Automatic Mode                                5   MAN / AUTO Mode Select                        5   DISCHARGES Selector                           5   INTERVAL Adjust                               6   METER CAL                                     6
2.3         Indicators                                    7
2.3.1       Status Indicators                             7     High Voltage Mode                             7   Voltage Range                                 7     High Voltage ON                               7     Polarity Mode                                 7     Charge/ Discharge Indicators                  8
2.3.2       Numeric Readouts                              8     Charging Voltage Readout                      8     AUTO MODE Count Indicator                     8
2.4         Output Panel                                  9

3.0         OPERATION                                     10
3.1         Initial Set-Up                                10
3.2         Charging Voltage Set-Up                       11
3.2.1       HOLD switch                                   11
3.2.2       Check COUNT/HOLD Switch                       11
3.2.3       HI/LO Voltage Select                          11
3.2.4       Polarity Select                               11
3.2.5       High Voltage ON                               11
3.2.6       High Voltage Level Adjustment                 12
3.3         MANUAL Mode of Operation                      12
3.3.1       MANUAL Mode Selection                         12
3.3.2       Discharge Pulse Generation                    12
3.4         AUTOMATIC Mode of Operation                   12
3.4.1       AUTOMATIC Mode Selection                      13
3.4.2       INTERVAL Adjustment                           13
PARAGRAPH    DESCRIPTION                                                PAGE
3.4.3        Discharge Pulse Count Setting                               13
3.4.4        Automatic Discharge Pulse Generation                        13
3.4.5        Interrupting the Count in the AUTO MODE                     14      HOLD Button                                                 14      RESET Button                                                14

4.0          CALIBRATION AND WAVEFORM VERIFICATION                       15
4.1          Human Body Model                                            15
4.1.1        Set-up                                                      15
4.1.2        Calibration Procedure                                       17      Rise Time and Ringing at 4kV                                18      Peak Current at 4kV                                         20      Fall Time at 4kV                                            19      Additional Information                                      19
4.2          Machine Model – ESD-S5.2 (Optional)                         19

5.0          DUT TESTING PROCEDURE                                       22
5.1          Set-Up                                                      22
5.2          Test Procedure                                              22
5.3          Testing to Method 3015.7 and ESD-S5.1                       23
5.3.1        Control Settings                                            23
5.3.2        Testing Procedure                                           24
5.4          Testing to ESD-S5.2 (Machine Model)                         24
5.5          Charged Device Model Testing-Std Model 910 Configuration    24
5.6          Charged Device Model Testing – Optional Configuration       25
5.6.1        Description                                                 26
5.6.2        Operation                                                   26

6.0          MAINTENANCE AND INTERNAL CALIBRATION                        26
6.1          General                                                     26
6.2          System Description – Functional Block Level                 26
6.2.1        Overview                                                    27
6.2.2        Detailed Description                                        28      Initial Application of Power                                28      High Voltage Turn-On                                        29      Automatic High Voltage Power Supply Shut Down               29      Polarity Selection                                          32      HI/LO Voltage Mode Selection                                32      High Voltage ON Detector                                    32      AUTO/MANUAL Mode Selection                                  33      Automatic Mode-Timer Interval Generation                    33      AUTO MODE Indicator Operation                               34     End of Test Detection – AUTO MODE                           34     Charge/Discharge Timing                                     34     Relay Drivers                                               35     Charge/Discharge Indication                                 35     CHARGING VOLTAGE DPM and Scaling Networks                   36     H.V. Relay Module                                           37   Charge/Discharge Cycle                                      37   HI/LO Voltage Mode Selection                                37     Low Voltage Power Supply                                    38     High Voltage Power Supply                                   39
6.3          Trouble Shooting and Repair                                 40
PARAGRAPH   DESCRIPTION                                             PAGE
6.3.1       Removal of Top and Bottom Covers                         40     Top Cover Removal                                        40     Bottom Cover Removal                                     40
6.3.2       Trouble Shooting Guide                                   41
6.4         Internal Adjustments                                     41
6.4.1       High Voltage Power Supply Output & DPM Calibration       41     High Voltage Mode Charging Voltage Level Calibration     42     Charging Voltage DPM Calibration HI Mode                 47     LO Voltage Mode Charging Voltage Level Calibration       47     Charging Voltage DPM Calibration / Low Mode              48
6.4.2       Output Pulse Timing Sequence Calibration                 48     Initial Set-Up, Oscilloscope Synchronization and         48
            Calibration of LB-U12     Calibration of U11, Discharge Pulse Width                49     Calibration of U15,Charge Relay Timing                   49     Final Check of Timing Sequence                           49
6.5         Human Body Model Values                                  50
6.5.1       Changing the Capacitor and Resistor                      50
6.6         Line Voltage Selection                                   51
6.6.1       Sub-Assembly Location                                    51
6.6.2       Interconnect Information                                 51

7.0         WARRANTY                                                 54

                      TABLE OF CONTENTS – FIGURES

FIGURE              DESCRIPTION                                     PAGE
1.1         Human Body Model Test Circuit                            1
2.1         Automatic Mode Timing Cycle                              6
2.2         Output Panel                                             9
3.1         Controls, Indicators, Outputs and Adapter Modules        11
4.1         Current Waveform per Method 3015.7                       16
4.2         Standard DUT Clamp Module Test Set-Up                    16
4.3         DUT Socket Module Test Set-Up                            17
4.4         Rise Time and Ringing Waveform at 4kV                    18
4.5         Peak Current at 4kV                                      18
4.6         Discharge Pulse Fall Time Measurement At 4kV             19
4.7         Current waveform through a short to ground               21
4.8         Current waveform through a 500 Ohm resistor to ground    21
5.1         Programming IC Adapter Modules                           23
5.2         MM classification and stress levels                      24
6.1         Model 910 Electrostatic Discharge Simulator              29
            Simplified Block Diagram
6.2         Electrostatic discharge Simulator                        30
            Detailed Functional Block Diagram
6.3         Output Pulse Timing Sequence                             34
6.4         Model 910 Electrostatic Discharge Simulator              37
            High Voltage Relay Module
6.5         High Voltage Power Supply- H.V. Test Point Location      47
6.6         HBM Plug-In RC Networks                                  50
6.7         P.C. Board Location                                      52
6.8         Sub-System Interconnection                               53

   The rapid advancement in the electronics industry during the past decade has placed an
   ever increasing importance on the understanding of electrostatics and its effect on
   electronic devices and systems. Electrostatic discharge is a common cause of
   microelectronic circuit failures. Some of these devices can be seriously damaged or
   destroyed by an electrostatic discharge below 20 volts. The sensitivity to ESD of other
   parts has also become evident through use, testing and failure analysis. The trend in
   technology towards greater complexity, increased packaging density and hence thinner
   dielectrics between active elements result in parts becoming even more sensitive to ESD.

   Failure mechanisms of electrical and electronic parts due to ESD typically include thermal
   breakdown, metalization melt and bulk breakdown which are power dependent; and
   dielectric breakdown, metalization to metalization arc over, surface breakdown and
   surface inversion which are voltage dependent.

   ESD can also induce latent failure mechanisms in both MOS structures and bipolar
   junctions in discrete devices and in microcircuits. This latent failure mechanism results in
   performance degradation and eventually a failure.

   Personnel are prime sources of ESD for damaging electrical and electronic parts.
   Electrostatic charges generated by rubbing or separating of materials are readily
   transmitted to a person’s conductive sweat layer charging that person. When a person
   handles or comes in close proximity to an ESD sensitive part, that part can then be
   damaged from a direct discharge by touching the part or by subjecting the part to an
   electrostatic field. The ESD from a human body can be reasonably simulated for test
   purposes from the circuit shown in Figure 1.1.

                                      Figure 1.1
                              Human Body Model Test Circuit

This circuit is the one specified in Mil-Std-883E, Method 3015.7 and ESD-S5.1 to represent a
human body for ESD testing. The human body capacitance, however, may be as high as
several thousand picofarads, but more typically 50 to 250 pf. Studies have shown that
approximately 80% of the population tested have a capacitance of 100 pf or less. The variation
in human capacitance is due to factors such as variations in the amount and type of clothing
and shoes worn by personnel and differences in floor materials. Human body resistances can
range from 100 to 100,000 ohms, but is typically between 1,000 and 5,000 ohms for actions
which are considered pertinent to holding or touching ESD sensitive parts or containers of ESD
sensitive parts. The variation in human body resistance is due to factors such as the amount of
moisture, salt and oils at the skin surface, skin contact area and pressure. A value of 1,500
ohms provides a reasonable lower human body resistance value. In view of the above, Mil-Std-
883E specifies a Human Body Model (HBM) using 100 pf discharged through 1,500 ohms. For
power sensitive parts, a change to a worst case Human Body Model capacitance (i.e., greater
than 100 pf) could result in damage to ESD sensitive parts at voltage levels below those shown
in Mil-Std-883E, Appendix 1. Therefore, a part which has been classified as non-ESD sensitive
could actually be ESD sensitive under more stringent Human Body Model conditions. For
voltage sensitive ESD parts, a variation in the capacitance value in the test circuit will not affect
ESD sensitivity. A decrease in Human Body Model resistance will increase the voltage and
power delivered to the ESD sensitive part and could adversely affect voltage and power
sensitive ESD sensitive parts at lower Human Body Model voltage levels. The Human Body
Model specified is considered a reasonable test circuit for evaluating the sensitivity of ESD
sensitive parts because personnel are generally the most common source of damaging ESD.

The Model 910 Electrostatic Discharge Simulator is an instrument specifically designed to
simulate the electrostatic discharge produced by human handling and meets all of the testing
requirements specified in Mil-Std-883E, Method 3015.7, ESD-S5.1 and JEDEC TEST METHOD

The Machine Model (MM) as defined in ESD-S5.2 is “An electrostatic discharge simulation test
based on a discharge network consisting of a charged 200 picofarad capacitor and (nominally)
zero ohms of series resistance. Actual series resistance and inductance are specified in terms
of the current waveform through a shorting wire. The simulation test approximates the
electrostatic discharge from a machine.” The Machine Model network is available as an option
to the Model 910.

To provide more comprehensive testing of components, the Model 910 utilizes individual plug-in
resistor and capacitor networks.


     2.1   General

            The Model 910 Electrostatic Discharge Simulator is designed to produce simulated
            discharge pulses which meet the requirements of Mil-Std-883E, Method 3015.7,
            and ESD-S5.1. The pulse amplitude may be set to any level from approximately 20
            volts to 8.25kV, and may be either positive or negative. Two voltage ranges are

provided; 0 to 2kV and 0 to 10kV. A digital readout is provided which indicates the
voltage level stored in the Human Body Model (HBM) capacitor prior to discharge.
In the Low Voltage Mode (0 to 2kV), the Digital Panel Meter (DPM) provides an
adjustment resolution of +1 volt. In the High Voltage Mode the resolution is +10
volts. Device testing may be performed either manually or automatically. In the
Manual Mode, the generation of each discharge pulses is controlled by the user. In
the Automatic Mode, the user selects the number of discharge pulses desired (0-9)
and the time interval between each pulse. When the DISCHARGE button is
depressed the correct number of discharges is produced. A HOLD button is
provided to halt the test sequence in the Automatic Mode or to prevent an
unintentional discharge in the Manual Mode.

Indicator lights on the front panel display the mode selected, the status (ON or
OFF) of the high voltage power supply output and the charge/discharge state of the
unit. A single digit LED indicator is also provided to indicate the number of
discharge pulses produced in the Automatic Mode and is extinguished in the
Manual Mode.

Adapter modules are available for holding a wide variety of devices and providing
for their connection to the OUTPUT terminals of the Discharge Simulator.

A front panel accessible calibration adjustment is provided to allow the user to
calibrate the digital panel meter to correspond to the actual charge on the HBM
capacitor. A detailed description of all controls and indicators is provided in the
following paragraphs.

2.2 Controls
All controls for operation of the Discharge Simulator are located along the front
edge of the unit. Four types of controls are used: two position push button
switches, momentary push button switches, rotary controls, and a ten (10) position
rotary switch. The states of the two position push button switches are indicated by
panel markings above and below each switch. The marking above each switch
defines the mode with the switch in the up position. Accordingly, the marking below
defines the state with the switch in the down position.

2.2.1 Main AC Power ON/OFF
This self latching (push-on-push-off) switch controls the AC power input to the unit.
When placed in the down position, the AC power will be ON and the front panel
indicator lamps will be illuminated.

2.2.2 High Voltage Controls High Voltage ON/OFF

             This switch (push-on-push-off) controls the high voltage output of the
             simulator. When in the down position, the high voltage output is

           turned on enabling the HBM capacitor to be charged to the level
           shown on the DPM. When this switch is in the OFF position (up), the
           high voltage output is disabled. High Voltage HI/LO Model Select

             This switch (push-on-push-off) selects either the LO Voltage Range
             (0 to 2kV) when in the up position or the HI Voltage Range (0 to
             10K) when in the down position. The unit will change modes only if
             the HIGH VOLTAGE ON/OFF switch is in the OFF (up) position.
             The mode LEDs directly below the DPM indicate the mode
             selected. NOTE: If the indicator lights indicate a mode which is
             different from that selected by the push buttons, the user must turn
             off the high voltage. The unit will then automatically switch to the
             correct mode. This is a safety feature which protects the unit’s
             internal components from switching when high voltage is present. High Voltage POLARITY (+/-) Select

             This switch (push-on-push-off) selects the polarity of the discharge
             pulse which is to be generated by the Discharge Simulator. When
             in the up position, a positive pulse is produced and when down, a
             negative pulse is produced. NOTE: As with the HI/LO Mode select
             switch, the Simulator will only respond to a change in the setting of
             the POLARITY select switch when the HIGH VOLTAGE ON/OFF
             switch is in the OFF position. High Voltage COARSE and FINE Adjust

             These two controls adjust the level of the high voltage stored in the
             Human Body Model capacitor. This voltage will be near zero with
             both controls fully counterclockwise and increases as each control
             is rotated clockwise. As its name indicates, the COARSE adjust
             control is used to set the high voltage level close to the desired
             level. The FINE adjust control is used for precise setting of this
             level. The adjustment range of the FINE control is approximately
             600 volts; thus, if this control is set to its mid-position (12 o’clock)
             before the COARSE control is set, it will allow the output level to be
             adjusted by approximately +300 volts about the COARSE control

2.2.3 Operating Mode Controls (LO and HI Ranges) Manual Mode

                              4 Manual / Auto Mode Select

               This push-push switch, when in the MAN (up) position,
               places the unit in the MANUAL mode. The AUTO MODE
               numeric indicator will be extinguished in this mode. DISCHARGE Control (Manual Mode).

               This momentary push button switch causes the Simulator
               to produce one discharge pulse each time it is depressed.
               In this mode, the user should allow a minimum of about
               one (1) second between discharge pulses.           If the
               discharge button is depressed more rapidly than once per
               second, an incomplete discharge cycle may be produced. HOLD button

               This push-push button, when in the COUNT (up) position,
               allows one discharge pulse to be produced with each
               depression of the DISCHARGE button. When placed in
               the HOLD (down) position, the Simulator is prevented
               from producing an output discharge pulse. This button
               should normally be left in the HOLD (down) position
               except when tests are being conducted. Using this control
               in this manner will insure that output pulses are obtained
               only when required and not at other times such as power
               up or during changing of test samples.   Automatic Mode MAN/AUTO Mode Select

               This push-push switch, when placed in AUTO (down)
               position, places the unit in the Automatic Mode. In this
               mode, the AUTO Mode numeric indicator will be
               illuminated. DISCHARGES Selector

               This ten-position switch selects the number of discharge
               pulses that will be automatically produced by the
               Simulator once the DISCHARGE button is depressed. It is
               set before the start of a discharge test sequence by
               rotating the control until the number on the control knob
               flange, corresponding to the desired number of pulses, is
               opposite the black pointer on the control panel.

                      5   INTERVAL Adjust

            This rotary control is functional only in the Automatic Mode and
            determines the time interval or delay between discharge pulses. The
            control is rotated clockwise to increase the time interval from a
            minimum of approximately 0.5 seconds to a maximum of 30 seconds.
            It should be noted that the interval setting of this control corresponds
            to the approximate “cool down” period between discharge cycles.
            Since each discharge cycle lasts about .650 seconds, the minimum
            discharge period (pulse to pulse duration) is about 1.1 seconds. This
            timing relationship is illustrated in Figure 2.1.

                           Figure 2.1
                  Automatic Mode Timing Cycle

              METER CAL

                                  This calibration control is used to decrease the
                                  value of the displayed charging voltage relative
                                  to the actual voltage stored in the Human Body
                                  Model capacitor. Adjustment of this control is
                                  discussed more fully in section 4.0. This control
                                  has been set at the factory and should be left in
                                  this position unless the instrument is being

2.3   Indicators

      The Model 910 Electrostatic Discharge Simulator employs solid state (LED)
      indicators for all status and numeric readouts. These are located on the
      vertical sloping portion of the enclosure above the control panel.

      2.3.1   Status Indicators

            High Voltage Mode

                    Voltage Range

                                       Two indicators are provided to indicate which
                                       of the two voltage modes the unit has been set
                                       for. The GREEN indicator will be on when
                                       the unit is in the LO Voltage (0 to 2kV) mode
                                       while the AMBER indicator will glow when the
                                       HI Voltage Mode has been selected. These
                                       indicators, which display the actual mode
                                       programmed, are controlled by the HI/LO
                                       select switch and the HIGH VOLTAGE
                                       ON/OFF switch.         When the High Voltage
                                       switch is in the ON (down) position, changes in
                                       the setting of the HI/LO mode select switch will
                                       be ignored by the system, and the status lights
                                       will not alter their indication. (See   Section

             High Voltage ON

                              This single red indicator will be illuminated when the
                              high voltage power has been turned on. It is a signal to
                              the operator that high voltage may be present
                              depending on the setting of the HI Voltage COARSE
                              and FINE adjust controls.

             Polarity Mode

                              Two indicators are provided to show which polarity has
                              been selected. An illuminated GREEN light indicates
                              that the output discharge pulse will be POSITIVE
                              relative to system ground while AMBER indicates that
                              the pulse will be NEGATIVE. Like the High Voltage
                              Mode indicators, the polarity may be changed via the
                              High Voltage +/- Polarity select switch only if the High
                              Voltage ON/OFF switch is in the OFF (up) position.

           Charging/Discharge Indicators

                            Two indicators are provided to display the
                            Charge/Discharge status of the Simulator. When the
                            GREEN Charge indicator is illuminated, the internal
                            circuits are in the Charge Mode, allowing the Human
                            Body Model capacitor to be charged to the desired
                            voltage level. The AMBER Discharge light will flash
                            when a discharge cycle is taking place, and the HBM
                            capacitor is connected to the OUTPUT terminal.

2.3.2   Numeric Readouts   Charging Voltage Readout

                  This readout is a 3½ digit LED display which provides the
                  operator with a direct indication of the high voltage level that is
                  charging the Human Body Model capacitor. In the LO Voltage
                  Mode (GREEN “LO (V)” indicator on), the readout indicates the
                  charging voltage directly in volts. In the HI Voltage Mode
                  (AMBER “HI (kV)” indicator on), a decimal point will appear on
                  the display and the charging voltage will be displayed in kilovolts.
                  Thus, in the HI Voltage Mode, a display of 6.83 indicates a
                  charging voltage of 6,830 volts (or 6.83 kilovolts). The display
                  also indicates the polarity of the charging voltage by the insertion
                  of a + or – to the left of the most significant digit.

                  In the LO (0 to 2kV) Voltage Mode, the readout is capable of
                  displaying a maximum level of 1,999 volts. If the operator sets
                  the Charging Voltage to a level above this maximum, the readout
                  will either begin to flash 1999 or blank out, depending on the type
                  of display used, indicating an overscale condition. This is normal
                  and the readout will not be damaged by settings above the
                  +1,999 volts. If it is desired to test above +1,999 volts, the HI
                  Voltage Mode should be used and the proper readout will be

 AUTO MODE Count Indicator

                  This display is a single digit LED numeric indicator which
                  displays the discharge pulse count in the Automatic Mode. In the
                  Manual Mode, this indicator is not illuminated. When the RESET
                  switch is depressed, the AUTO Mode count indicator will reset to
                  zero and hold this count until the discharge cycle is started.
                  Once the discharge cycle is started, the AUTO Mode count

                      indicator will automatically increase its count by one for each
                      discharge pulse produced. Upon reaching the count set on the
                      DISCHARGES selector, automatic test cycling is terminated and
                      the AUTO Mode indicator will hold the final pulse count until the
                      RESET button is again depressed.

                      If, during an automatic test cycle, the HOLD button is depressed,
                      the AUTO Mode pulse counter will display the total number of
                      discharges produced up to the time the HOLD button was
                      depressed. If the HOLD button is now placed in the COUNT (up)
                      position, and the DISCHARGE button is depressed, the test
                      cycle will resume and the remaining pulses as set on the
                      DISCHARGES control, will be produced.

2.4 Output Panel

    The Output Panel, shown in Figure 2.2 is located on the right side of the instrument
    output jacks. The R-C modules are easily replaced by unplugging them from the

    The CURVE TRACER output is a standard banana jack that is connected to a high
    voltage relay. When the system is in the Charge Mode the relay is closed
    connecting the CT output to the Discharge Resistor. This connects the CT output to
    the pin under test: When the system is in the Discharge Mode the relay opens,
    thereby disconnecting the CT output from the DUT. It again closes when the system
    returns to CHARGE. This enables the user to check the DUT both prior to and after
    a discharge without removing any connectors.

    The CURVE TRACER output is not connected when shipped from the factory. If the
    user wants to use this function the top cover must be removed and the CT .040” pin
    must be plugged into the .040” jack located on top of the discharge relay. DO NOT
    USE ABOVE 5kV. Induced voltages may damage the Curve Tracer. User must
    determine suitability before using.

                               Figure 2.2 Output Panel


   3.1 Initial Set-Up

      3.1.1 Before connecting the Simulator to the AC line, set the controls on the
            front panel to the following positions:

              1. POWER ON/OFF - OFF (up)
              2. HIGH VOLTAGE ON/OFF - OFF (up)
              3. High Voltage COARSE and FINE adjust – both fully counterclockwise
              4. COUNT/HOLD switch - HOLD (down)

      3.1.2 Before connecting the AC line cord to the power outlet, check the
            VOLTAGE SELECT switch on the rear panel to ensure that the unit is
            set for the correct line voltage. This switch enables the user to select
            100, 110, 220 or 240 VAC, 50/60 Hz operation.

      3.1.3 Attach the appropriate Test Adapter Module by pressing it gently into the
            four mounting jacks located on the front panel as shown in Figure 3.1.

      3.1.4 Secure the device under test (DUT) to the holding fixture on the test
            adapter plate using the spring loaded clamp. If necessary, manually
            adjust the sliding post to provide the proper spring loaded force on the
            DUT. NOTE: When properly adjusted, the DUT will be securely held
            but may be removed by sliding the spring loaded half of the holding
            fixture to the right.

      3.1.5 Plug the red minigrabber test lead into the red OUTPUT jack and the
            black minigrabber test lead into the GND jack. If a curve tracer or other
            test instrument is to be used to check the characteristics of the Pin Pair
            of the DUT before and after a discharge sequence, plug it into the
            CURVE TRACER output banana jack.

      3.1.6 Connect the test lead spring loaded minigrabbers to the appropriate
            leads on the DUT. For the best possible output waveshape, the leads
            should be positioned such that they are away from one another by a
            minimum of ¾” and away from the unit’s chassis (ground). The test
            leads should not be reversed when the opposite polarity is desired.

      3.1.7 Turn on the Discharge Simulator power by placing the POWER ON/OFF
            switch in the ON (down) position. The Power ON state will be indicated
            by illumination of the colored status indicators and possible minor
            flickering of the Charging Voltage readout. The AUTO Mode indicator
            may or may not be illuminated depending on the setting of the
            AUTO/MAN select switch.

3.2    Charging Voltage Set-up

        The Procedure described in this section is common to both the Manual and
        the Automatic Mode and should be followed independent of the mode

       3.2.1 HOLD Switch

       3.2.2 Check to see that the COUNT/HOLD switch is in the HOLD (down)

      3.2.3 HI/LO Voltage Select

            Select the desired operating voltage by placing the High Voltage HI/LO
            switch in the LO position (up) for testing below 2000 volts or in the HI
            position (down) for testing at or above 2000 volts.

                                            Figure 3.1
                       Controls, Indicators, Outputs and Adapter Modules

      3.2.4 Polarity Select

            Set the POLARITY switch to the desired output pulse polarity: up for
            positive, down for negative.

      3.2.5 High Voltage ON

            Depress this pushbutton to turn on the high voltage.

        3.2.6 High Voltage Level Adjustment

              Rotate the FINE adjust control clockwise until the pointer is in the
              twelve o’clock position. Rotate the COARSE adjust control clockwise
              until the approximate desired voltage level is indicated on the
              CHARGING VOLTAGE readout. Now re-adjust the FINE control to trim
              the voltage reading to the final level. Allow several seconds for the
              reading to stabilize, then, if necessary, re-adjust the FINE control. The
              unit is now ready to produce the desired output pulse.

3.3 MANUAL Mode of Operation

   In the MANUAL Mode, the operator is in complete control of the number of pulse
   discharges and the interval to be impressed on the DUT. To operate the
   Discharge Simulator in this mode, follow the procedure in sections 3.1 and 3.2,
   then proceed as described in the following sub-paragraphs.

       3.3.2 MANUAL Mode Selection

             Set the AUTO/MAN button to the MAN (up) position.

       3.3.2 Discharge Pulse Generation

             Set the COUNT/HOLD button to the COUNT (up) position. Depress the
             DISCHG. button once each time a high voltage discharge pulse is
             required. The AMBER DISCHARGE indicator will flash each time an
             output pulse is produced. At least one second should be allowed
             between pulses for the “cool down” period. After the DUT has been
             subjected to the desired number of pulses, place the COUNT/HOLD
             button in the HOLD (down) position, and turn off the high voltage supply
             by placing the High Voltage ON/OFF switch in the OFF (up) position.

             To resume testing, turn on the High Voltage, if necessary re-adjust the
             FINE control, set the COUNT/HOLD button to COUNT, and when ready,
             depress the DISCHG. button.

 3.4     AUTOMATIC Mode

          In the Automatic Mode, the operator selects the number of discharge pulses
          desired and the interval between pulses. Upon depression of the RESET
          then the DISCHG. buttons, the Simulator proceeds to automatically generate
          the selected number of pulses at the chosen interval. The HOLD button may
          be used to hold the count at any time before the selected count is reached.
          To operate the Automatic Mode, follow the set up procedures in 3.1 and 3.2
          then proceed as described in the following sub-paragraphs.

3.4.1   AUTOMATIC Mode Selection

        Set the MAN/AUTO switch to the AUTO (down) position. The AUTO
        Mode numeric indicator will now be illuminated.

3.4.2. INTERVAL Adjustment

        The INTERVAL adjust control, which provides for setting the “cool
        down” time interval between discharges is an uncalibrated control,
        and if accurate timing is required, must be calibrated against an
        external reference (e.g., digital watch, stopwatch with sweep hand,
        etc.). To accurately set the INTERVAL control, turn off the internal
        High Voltage Supply by setting the High Voltage ON/OFF switch to
        OFF (up). Set the INTERVAL control to 9, the COUNT/HOLD switch
        to COUNT, depress the RESET switch, and when ready, depress the
        DISCHG. Switch. Using an external timing reference, measure the
        time interval between flashes of the AMBER DISCHARGE light.
        Adjust the INTERVAL control until the desired “cool down” period is
        obtained. (NOTE: The discharge cycle time has been set during
        assembly to .65 seconds, hence, the “cool down” time will be the time
        measured between flashes of the amber DISCHARGE light minus
        .65 seconds. Refer to Figure 2.1). After calibration, set the
        COUNT/HOLD switch to HOLD and turn on the High Voltage supply
        setting the High Voltage ON/OFF switch to ON.

3.4.3   Discharge Pulse Count Setting

        To select the number of discharge pulses, rotate the DISCHARGE
        selector until the desired number is opposite the point marking on the

3.4.4   Automatic Discharge Pulse Generation

        Set the COUNT/HOLD button to the COUNT (up) position. Depress
        the RESET button to set the AUTO MODE counter to zero. When
        ready to start the automatic test sequence, momentarily depress the
        DISCHARGE button. The Automatic Mode timing sequence starts
        with the interval delay, hence, the first discharge pulse will not occur
        until the INTERVAL time has lapsed. Upon reaching the end of the
        first interval, the AMBER DISCHARGE indicator will flash, the AUTO
        MODE indicator will advance to the count of one and the first
        discharge pulse will be generated. This sequence will continue until
        the AUTO MODE readout displays the same number as set on the
        DISCHARGES Selector. At the time, the test is concluded, the
        Simulator automatically stops generating output discharge pulses,

                  and the AUTO MODE readout displays the final count of the number
                  of discharges produced.

                  Nothing further will occur unless the operator wishes to repeat the
                  test sequence. To do this, momentarily depress the RESET button,
                  then depress the DISCHARGE button. The automatic discharge
                  cycle will be repeated

                  After completion of testing, place the COUNT/HOLD button in HOLD
                  and set the High Voltage switch to OFF.

        3.4.5     Interrupting the Count in the AUTO MODE

                  To stop the discharge pulses in the AUTO MODE before the full
                  count is reached, two (2) methods may be used.

         HOLD Button

                          If the HOLD button is depressed while automatic testing is in
                          progress, and the full count as set on the DISCHARGES
                          control has not yet been reached (AUTO MODE indicator
                          DISCHARGES setting), the discharge pulses will be stopped
                          and the AUTO MODE indicator will hold the discharge pulse
                          count as produced up to that point. To complete the
                          unfinished count, set the COUNT/HOLD button to COUNT
                          and then depress the DISCHARGE button. Unless the
                          DISCHARGE button is depressed after the COUNT/HOLD
                          button is set to COUNT, the automatic discharge sequence
                          will not be resumed.

         RESET Button

                          If the RESET button is depressed while the automatic
                          discharge is in progress, the AUTO Mode count will
                          immediately reset to zero, and, upon release of the RESET
                          button, and depression of the DISCHARGE button, the
                          discharge sequence will start again, from zero.




      4.1   Human Body Model – Mil-Std 883E, Method 3015.7, ESD-S5.1 & JEDEC

            These test methods require system calibration utilizing the discharge pulse
            current waveform. The Human Body Model is C=100pf and R=1500 ohms.

            The waveform must be verified using both + and –4kV charging voltages.
            The discharge current must be within +10% of the specified Ip value ( 2.67

            Photographs of the rise time, fall time, and peak current calibration are

            Figure 4.1 shows the waveform requirements specified in Method 3015.7
            and ESD-S5.1.

            4.1.1 Set-Up

                  A high speed oscilloscope and current probe with a bandwidth of at
                  least 350 MHz and a visual writing speed 4 cm/nsec minimum are
                  required.    Scopes satisfactory for this measurement are the
                  Tektronix Model 2467 high speed oscilloscope or the Model 7834 or
                  7934 storage oscilloscopes. A Digital Storage Oscilloscope (DSO)
                  may also be used if its frequency (350 MHz or better) and sampling
                  rate (1 GS/sec or better is used. Tektronix TDS 300 and 3000 series
                  oscilloscopes meeting this criteria are satisfactory. Tektronix Models
                  CT-1 or CT-2 current transducers are satisfactory for detecting the
                  current pulse.

                  The 50 ohm impedance of the current probe must be matched to the
                  input impedance of the oscilloscope. For those scopes with only a 1
                  Megohm input impedance, an adaptor is available to match the 50
                  ohm impedance of the probe to the 1 megohm impedance of the

                  Because of the very high frequencies being measured it is
                  recommended that the current probe cable be double shielded.



           pulse shall have the following characteristics:

                  Tr     (rise time)            2-10 nanoseconds
                  Td    (decay time)            150 +20 nanoseconds
                  Ip    (peak current)          within +10%
                  Ir    (ringing)               The decay shall be smooth, with
                                                 ringing, break points, double time
                                                 constants or discontinuities less
                                                 than 15% Ip maximum, but not
                                                 observable 100 nanoseconds after
                                                 start of the pulse.

                                    Figure 4.1
                        Current Waveform per Method 3015.7

A 1.25 inch, 18 gauge wire is required to connect the current probe to the output
connectors of the Model 910. Figure 4.2 shows the test set-up for the standard DUT
clamp module and Figure 4.3 shows the test set-up for an IC Adapter Module.

                                     Figure 4.2
                       Standard DUT Clamp Module Test Set-Up

                                   Figure 4.3
                          DUT Socket Module Test Set-Up


The current probe (Tek CT-1) is polarized and is marked with a + on one side. When
verifying a positive discharge pulse, the OUTPUT signal from the 1.5K ohm resistor
should be connected to this side. When verifying a negative discharge pulse, the GND
connection should be connected to this side. No changes in scope setting are

      4.1.2 Calibration Procedure

   Rise Time and Ringing at 4kV

                     Set the scope vertical amplifier sensitivity to 2 volts/Div and the
                     time base to 5 nsec/Div. Switch the vertical amplifier out of the
                     CAL position and adjust the vernier such that a discharge pulse
                     will go from the “0” graticule marking to the “100” graticule
                     marking as shown in Figure 4.4. The rise time is defined as the
                     time for the leading edge to rise from the 10% point to the 90%
                     point. The specification calls for a rise time between 2 and 10
                     nsec. For the Model 910 ESD Simulator the rise time will
                     normally fall between 2.5 and 6 nsec. The peak-to-peak ringing
                     must be less than 15% of Ip.

                         Figure 4.4
           Rise Time and Ringing Waveform at 4kV Peak Current at 4kV

    Set the scope vertical amplifier sensitivity to the calibrated 2
    volts/Div. and keep the time base set to 5 nsec/Div. Adjust the
    vertical position such that the base line is on the first graticule
    line. This now provides a voltage measurement range of 16
    volts.    If the CT-1 probe is used then the total current
    measurement range is 3.2 amps (CT-1 Probe calibration is 5
    volts/amp). Probes with different calibration will necessitate
    using different scope vertical amplifier settings. At a charging
    voltage of 4kV, the peak current, Ip, must be 2.67 amps +10%
    (2.40-2.93 amps). Figure 4.5 shows the peak current at 4kV.

                          Figure 4.5
                      Peak Current at 4kV

                        18 Fall Time at 4kV

        Set the scope vertical amplifier sensitivity to the UNCAL 2
        Volts/Div. setting as was done for the rise time measurement.
        Set this time base to 20 nsec/Div. The discharge pulse should
        resemble that shown in Figure 4.6. The fall time (decay time)
        must be 150 +20 nsec from the 100% point to the 37% point.

                          Figure 4.6
         Discharge Pulse Fall Time Measurement at 4kV Additional Information

        The measurement of the current waveform can be significantly
        affected by the test instrument used. Excessive ringing and poor
        waveform characteristics could be a result of an incorrect test set-
        up or an oscilloscope that is not adequately shielded.

        The charging voltage calibration is preset at the factory. No field
        adjustment should be made to the METER CAL adjustment.

        The Model 910 incorporates a curve tracer output. The CURVE
        TRACER output connector is connected to the output side of the
        discharge relay when in the CHARGE Mode and is disconnected
        from this point during the DISCHARGE cycle. This switching
        function is accomplished by a high voltage relay. This relay, since
        it is part of the discharge circuit, does affect the purity of the

              discharge waveform. Disconnecting this relay from the discharge
              relay will reduce the ringing associated with the current waveform.

              ESD-S5.1 also requires an additional calibration waveform using
              a 500 ohm resistor to ground.

              Other standards such as the JEDEC standards reference Method
              3015.7 and/or ESD-S5.1. The specific standard to which testing
              will be performed should be referred to for the correct calibration
              of the Model 910 ESD Simulator.

4.2 Machine Model – ESD-S5.2 (Optional)

   This standard requires system calibration utilizing the discharge pulse
   waveform obtained from a 200 pf capacitor discharged through 0 Ohms to
   ground. The same oscilloscope and current transducer setup used for HBM
   verification are used for the MM verification waveforms.

   The waveform must be verified using both + and -400 Volts through both a
   short circuit to ground and through a 500 Ohm resistor. Other stress levels of
   100, 200 and 800 Volts may be performed using only the discharge through
   a short to ground.

   A photograph or printout of the waveforms are required.

    Figure 4.7 shows the waveform requirements for the discharge through a
    short to ground at 400 Volts and Figure 4.8 shows the waveform
    requirements through the 500 Ohm resistor to ground.

        The MM capacitor is keyed so when MM testing is selected the HI
        RANGE is disconnected and only the LO RANGE can be used. This
        allows MM testing from less than 20 Volts to 200 Volts.

                    Figure 4.7
     Current waveform through a short to ground

                     Figure 4.8
Current waveform through a 500 Ohm resistor to ground


      5.1   Set-Up

            Set the High Voltage controls to the desired Range and Polarity. Turn the
            HIGH VOLTAGE ON and adjust for the desired voltage level. Set the
            COUNT/HOLD switch to HOLD (button pushed in).

            Insert the DUT into either the clamping fixture or the appropriate optional
            zero insertion force socket adapter module. Connect the minigrabber or to
            the desired pin pairs when the clamping fixture is used.

            If one of the socket adapter modules is used follow the procedure
            described in Figure 5.1 on how to program the module for the desired pin
            group configurations. Use the .080” plug cables to connect the socket
            module to the Simulator output jacks.

      5.2   Test Procedure

            If manual operation is desired, select MAN mode (button up). Set the
            COUNT/HOLD button to COUNT. Depress the DISCHARGE button to
            initiate a discharge across the DUT. Each time the DISCHARGE button is
            depressed a discharge will occur.

            To reverse polarity, turn the HIGH VOLTAGE to OFF and set the
            COUNT/HOLD button to HOLD, depress the POLARITY button for either +
            or -, then turn the HIGH VOLTAGE back on and set the COUNT/HOLD
            button to COUNT. NOTE: The HIGH VOLTAGE must be turned off before
            Polarity or Range can be changed.

            If the AUTO Mode is desired, set the OPERATING Mode controls to AUTO
            and HOLD. Select the number of discharge pulses (1-9) and cool down
            interval period button to start the test sequence. The first discharge will
            occur after the INTERVAL time selected has elapsed. Each discharge will
            register on the AUTO Mode display until the total number of cycles have
            been completed.

            To interrupt the test cycle, set the COUNT/HOLD button to HOLD. To
            resume the test, depress the DISCHARGE button. To start a new cycle,
            depress the RESET button, then depress the DISCHARGE button.

                                    Figure 5.1
                          Programming IC Adapter Modules

5.3   Testing to Method 3015.7 and ESD-S5.1

      A sample of devices shall be characterized for the device ESD failure
      threshold using voltage steps of 500. 1000, 2000 and 4000 Volts as a
      minimum. Finer voltage steps may optionally be used to obtain a more
      accurate measure of the failure voltage. Testing may begin at any voltage
      step, except for devices which have demonstrated healing effects,
      including those with spark gap protection, which shall be started at the
      lowest step. Cumulative damage effects may be eliminated by retesting at
      the failure voltage step using a new sample of devices starting at one or
      two voltage steps lower than the failure threshold.

      5.3.1 Control Settings

            Initially set the Range to LO, the Polarity to + and adjust the level to
            500 volts.       Select the AUTO Mode and set the number of
            DISCHARGES to 3 and the INTERVAL (cool down period) to a
            minimum of 1 second.

     5.3.2 Testing Procedure

           Refer to the appropriate test standard being used to establish the
           correct testing protocol (starting voltage, number of discharges, pin
           combinations, etc).

5.4 Testing to ESD-S5.2 (Machine Model)

   Machine Model testing is described in ESD-S5.2 which is available from the
   ESD Association at 7900 Turin Road, Rome, NY 13440. This Standard
   defines five component classification levels and four stress levels as shown
   in Figure 5.2. Testing protocol and pin combinations are also defined.

                                    Figure 5.2
                        MM classification and stress levels

5.5 Charged Device Model Testing - Standard Model 910 Configuration

   The standard Model 910 is not specifically designed to perform Charged
   Device Model testing. However, the charging system of the Model 910
   incorporates a 400 Megohm resistor in the charging circuit. This allows an
   isolated device to be charged slowly enough not to cause an ESD discharge
   as specified in current CDM standards. ETS can provide a module with a
   lead and a minigrabber that replaces the plug-in capacitor module plus a
   ground lead. It is up to the user to configure the placement of the DUT per
   the applicable standard.

   To perform a CDM test, the following procedure may be used:

           1. Set the HVPS to the desired voltage level then turn the HVPS to

           2. Connect the red mini-grabber to the desired pin(s).

           3. Turn on the HVPS.

           4. Remove the minigrabber from the DUT and immediately touch the
              specified pin(s) with the short ground black lead provided .

5.6 Charged Device Model Testing - Optional CDM Modification

   5.5.1 Description

          The standard ETS Model 910 ESD Simulator can perform both
          Human Body and Machine Model discharges. In both cases a
          capacitor is charged and then discharged through a resistor (which
          can be as low as 0 Ohms) via a relay closure. The rise times
          associated with these Models are in the nanosecond range.

          The Charged Device Model (CDM) is when the device is charged and
          then discharged directly to ground. To create a CDM the Device
          Under Test (DUT) is charged as if it was the capacitor and then
          discharged by grounding the desired pin using a reed relay. The
          existing 400 megohm resistor in series with the charging circuit
          provides a slow enough rise time as not to damage the DUT. The
          ESD Association STM 5.3 for charged device model testing specifies
          a minimum series resistance of 100 megohms. The rise times
          associated with a CDM discharge are in the picosecond range.

          The Model 910 can be configured to perform CDM testing. The
          modification consists of adding a 3-position switch to control the
          charging function, the addition of a grounding relay with its own
          dedicated input banana jack and a charging module that replaces the
          capacitor module.

          ETS does not specify CDM waveforms that may be obtained from
          the Model 910. However, experience has shown that CDM testing
          using the Model 910 gives satisfactory results in describing the
          CDM sensitivity of devices.

   5.6.2 Operation

          To perform HBM and MM testing the added lever switch must be in
          the up (HBM/MM) position. This connects the charging relay to the
          charging circuit. When this switch is in the center (OFF) position, the
          charging relay is disconnected and no high voltage will be present at
          the Capacitor Module.

          To perform CDM testing, first place the HBM/MM lever switch in the
          OFF (center) position, then replace the capacitor module with the

                 CDM module, the one with the red banana jack installed. Next, plug
                 the red MM minigrabber cable into the red charging module banana
                 jack and the black cable into the green grounding jack. NOTE: The
                 MM cables are the ones without the black shrink tubing around
                 the banana plug. Connect the red minigrabber to the pin(s) on the
                 DUT that is being charged and the black minigrabber to the pin(s) that
                 are to be discharged.

                 Turn on the High Voltage and adjust to the desired voltage level and
                 polarity. Depress and hold the spring-loaded lever switch for
                 approximately one (1) second. Immediately upon releasing the switch
                 depress the DISCHARGE pushbutton switch. This will activate the
                 dedicated grounding relay. Repeat the CHARGE/DISCHARGE cycle
                 for each test.


      6.1   General

            The purpose of this section is to provide information about the design and
            function of the Model 910 Electrostatic Discharge Simulator. This
            information will enable the user to check and/or adjust the few internal
            timing sequences which control the CHARGE/DISCHARGE cycle and to
            make simple repairs should a component failure occur. The fault diagnosis
            and repair procedures covered here will enable faults to be located to the
            user replaceable plug-in IC level. Repairs involving replacement of
            soldered-in components should be made by qualified personnel only and
            may be best handled by returning the equipment to ETS. Should it become
            necessary to return the equipment for repair, it is necessary that it be
            adequately packed for shipping ( use of the original shipping container and
            packing is highly recommended ) and that a detailed description of the
            malfunction be furnished with the equipment. It is further recommended
            that ETS be contacted prior to the return of any equipment.

            POWER IS 115 (OR 220 VAC) 50/60 Hz. ALTHOUGH PRECAUTIONS
            AND/OR EQUIPMENT.

6.2    System Description-Functional Block Level

       Contained in this section is a functional description of the Discharge
       Simulator circuits. Signal flow paths will be traced from their origins,
       through control logic and timing to their destinations as output or display
       functions. Also provided will be circuit board and component reference
       designation information which should aid the user in locating specific
       components. Table 6.1 should be used as a key to this information.

                                      TABLE 6.1

                                      Symbol Key

       Symbol             Component Location and Identification Key

        LVPS                LOW VOLTAGE POWER SUPPLY
        HVPS                HIGH VOLTAGE POWER SUPPLY
        CP                  CONTROL PANEL
        LB                  LOGIC BOARD
        HVRM                HIGH VOLTAGE RELAY MODULE
        DRM                 DISPLAY / READOUT MODULE
        DPM                 DIGITAL PANEL METER

      6.2.1 Overview

            Figure 6.1 is a simplified block diagram which shows the functional
            relationship between the major blocks in Table 6.1. As can be seen,
            the system circuits are contained on seven (7) printed circuits boards
            with part numbers ETS-901 through ETS-907. Figure 6.2 is a
            Detailed Functional Block Diagram of the Model 910 ESD Simulator.
            All operator initiated functions are generated via the system Control
            Panel (CP). The Control Panel interfaces with the Logic Board (LB),
            the High Voltage Power Supply (HVPS) and the Display/Readout
            Module (DRM). It also provides the Power ON/OFF function for the
            system. The line voltage is wired directly to the Power Control switch
            on the P.C. Board, so care must be exercised when the bottom cover
            is removed and the system is under going maintenance, repair and/or

            The Logic Board (LB) receives its inputs from the Control Panel (CP)
            and generates timing and control signals which are used by most of
            the other assemblies (HVPS, HVRM, DRM, DPM). The HVPS
            receives an ON/OFF signal and output level information directly from
            the CP as well as other control signals from the LB. The AUTO
            Mode illumination signal is also generated by the CP and is fed
            directly to the DRM.

        The High Voltage Relay Module (HVRM) contains two (2) high
        voltage relays which are controlled by the LB and provide the
        charging and discharging functions related to producing the ESD
        output pulse. Care must be exercised in this area during
        maintenance since voltages on the order of +10kV can be present
        even when the system is off and has been disconnected from the AC

        The HVRM also contains resistor networks which limit current surges
        during charging and generate an output signal for the DPM.

        The Display/Readout Module (DRM) displays mode information,
        CHARGE, DISCHARGE, and H.V.ON status, and contains the 0-9
        Numeric AUTO Mode indicator. It is controlled primarily by the LB.

        The High Voltage Power Supply (HVPS) generates the charging
        voltage which is used to produce the ESD Output Pulse. It can
        generate up to +10kV as determined by the CP and LB.

        The Low Voltage Power Supply (LVPS) accepts unregulated power
        from the AC Line via the power transformer. It produces regulated
        D.C. outputs of +5,+12, and –12 volts and unregulated D.C. outputs
        of +22 and +34 volts.

        The DPM is a 3½ digit LED readout capable to reading up to 1999.
        Readings in excess of this cannot be displayed and are indicated by
        either on/off flashing or blanking of the indicator. In the Low Voltage
        Mode, the meter reads directly in volts. In the High Voltage Mode, a
        decimal point is illuminated and, in conjunction with an internal
        controlled automatic scale change, the meter reads in kV. This DPM
        assembly contains circuits which are very sensitive to High Voltage
        discharges, consequently it is recommended that the DPM be
        disconnected if the high voltage power supply and/or switching
        module is to be serviced.

6.2.2   Detailed Description

        The overview in the preceding paragraph will now be expanded to
        provide specific information which will be of value in repairing this
        unit. References will be made to specific components involved in the
        processing of the signals discussed. The mnemonics shown in Table
        6.1 will be used and may be followed by one or more specific
        component reference designators.

                                 28   Initial Application of Power

          The system is designed to power up (CP-S1) in the reset
          state. If in the AUTO Mode when power is applied, the
          AUTO Mode indicator will display zero and the system will
          remain in the CHARGE state until the DISCHARGE button
          (CP-S9) is depressed.     The initial start up reset is
          generated by LB-U6 which resets LB-U3, U7 and U1.   High Voltage Turn-On

          The HVPS is enabled by depressing the High Voltage ON
          push button which applies power to the driver stage of the
          HVPS. The output level of the variable L.V. supply is
          determined by setting of the FINE and COARSE controls
          (CP-R1-COARSE and R2-FINE).   Automatic High Voltage Power Supply Shut Down

          The Logic Board (LB) contains a circuit (LB-U10) which
          monitors the CP switch settings (CP-23 & S4) and the
          states of the polarity control flip flop (LB-U9) and the HI/LO
          flip flop (LB-U8). If an error exits between a CP switch
          setting and any flip flop state, a signal called RPSD
          (Remote Power Shut Down) is generated (LB-U10) and
          reduces the H.V. output to zero. RPSD is fed to the Driver
          and Variable L.V. sections of the HVPS.

          When RPSD is a logic “1” (+5 Volts) both sections of the
          HVPS are shut down as a fail safe measure.

                Figure 6.1
Model 910 Electrostatic Discharge Simulator
        Simplified Block Diagram

                                  Figure 6.2
Model 910 Electrostatic Discharge Simulator-Detailed Functional Block Diagram

                                     31   Polarity Selection

          Polarity selection is initiated at the Control Panel (CP-S4).
          The two (2) signals generated set (or reset) the polarity
          control flip flop (LB-U9). If the High Voltage switch is in the
          ON position when the polarity switch is activated, LB-U9
          will ignore the CP-S4 signals and will not change state.
          Instead, RPSD is generated causing the H.V.P.S. to shut
          down. If the H.V. switch is off when CP-S4 is activated, the
          polarity control flip flop (LB-U9) will change state
          accordingly. The positive polarity lamp and relay driver for
          the green positive polarity indicator (DRM-DS5) and the
          positive polarity select relays (HVPS-RL1 and RL2) is LB-
          Q7. The negative polarity lamp and relay driver is LB-Q8.
          The signal it produces drives the amber negative polarity
          indicator (DRM-DS6).

          Polarity selection is accomplished at the H.V. level by
          switching action of the four (4) H.V. relays (HVPS-RL1, 2,
          3, & 4) in the HVPS.   HI/LO Voltage Mode Selection

          Mode selection is initiated at the Control Panel (CP-S3).
          The two (2) signals originate at the CP set (or reset) the
          HI/LO Mode control switch is activated, LB-U8 will not
          change state. Instead, the HVPS is shut down via the
          action of LB-U10 and the RPSD signal. The output of the
          HI/LO Mode control FF (LB-U8) is fed to lamp and relay
          drivers. The LO Voltage Mode lamp driver is LB-Q4. Its
          output drives the green low voltage indicator (DRM-DS2).
          The High Voltage Mode driver is LB-Q6. Its output drives
          the amber HI Mode indicator (DRM-SD3) and the scale
          change relay (HVRM-RL3).   High Voltage ON Detector

          To prevent hot switching of the various relays used
           throughout the system and to provide the equipment
           operator with a visual indication when a charging voltage
           is present, a voltage sensing circuit is employed. The
           output of the Variable L.V. Supply is fed to the HV ON
           detector (LB-U13 and U14). The HV ON detector is a two
           (2) state circuit consisting of an amplifier (LB-U14)
           followed by a comparator (LB-U13). The comparator (LB

           -U13) output is fed to the H.V. lamp driver (LB-Q2). The
          lamp driver output is fed back to the Polarity and Mode
          Control circuits to act as an inhibit signal as described in
 and The lamp driver output also drives
          the red H.V. ON lamp (DRM-DS4). A failure in the H.V.
          ON detection circuit which causes the H.V. ON indicator to
          stay on will inhibit Mode and Polarity changing by the
          operator.   AUTO/MANUAL Mode Selection

          Auto/Manual selection is accomplished by activating the
          AUTO/MAN button on the control panel (CP-S6). This
          switch performs three (3) functions. When in the Manual
          mode (MAN), it resets the AUTO Mode Run/Hold flip flop
          (LB-U7, U1) preventing the automatic generation of H.V.
          output discharge pulses. It also enables the manual pulse
          generator (LB-U4) so that output pulses may be
          generated at will by the user, and extinguishes the AUTO
          Mode indicator (DRM-DS1).

          In the Automatic Mode, the AUTO/MAN select switch
          illuminates the AUTO Mode 0-9 indicator (DRM-DS1), and
          removes the Reset from the Run/Hold flip flop (LB-U7,
          U1), allowing output pulse generation to occur
          automatically (upon depression of the DISCHARGE
          button (CP-S9)). It also selects the AUTO Mode trigger
          pulse which is generated by the AUTO Mode interval timer
          (LB-U5).   Automatic Mode-Timer Interval Generation

          When the AUTO Mode is selected by depressing the
          AUTO/MAN button (CP-S6), automatic output pulse
          generation is enabled. Upon depressing of the
          DISCHARGE button (CP-S9), the Run/Hold flip flop is set
          to the RUN state. LB-Q1 is turned off allowing capacitor
          LB-C2 to start charging. The charging rate is determined
          by the setting of the INTERVAL control (CP-R3). At the
          end of the timing interval, the output of the interval timer
          (LB-U5) goes back to zero. This generates the AUTO
          Mode trigger pulse which starts the automatic output pulse
          generation sequence. The timing of the next interval is
          delayed until the output pulse timing sequence is

                       33   AUTO MODE Indicator Operation

          Each time the interval timer (LB-U5) reaches the end of a
          timed interval, it generates a low going trigger pulse. This
          signal is inverted by gate LB-U7 and is applied as a clock
          to the binary counter LB-U3. The binary counter output is
          converted to the drive signals for the AUTO Mode
          indicator by the binary to 7-segment decoder driver (LB-
          U2). When the RESET button is depressed (CP-S8), the
          binary counter (LB-U3) is reset via the negative going
          output of U6. The output of the 7-segment decoder driver
          (LB-U2) is fed to the 7-segment LED display (DRM-DS1)
          and causes the proper number to be displayed. End of Test Detection – AUTO MODE

          The output of the binary counter (LB-U3) is decoded by the
          action of the DISCHARGES selector (CP-S5) and a logic
          decoder gate (LB-U1) in the 0-9 comparator block. When
          the binary counter output (LB-U3) reaches the count
          selected by the DISCHAGRES selector (CP-S5), decoder
          gate (LB-U1) produces a reset signal which resets the
          COUNT/HOLD control flip flop in the discharge control
          block until the DISCHARGE button is again depressed to
          start a new test sequence. Charge/Discharge Timing

          The proper sequence and pulse duration of the
          Charge/Discharge timing is determined by three (3) one-
          shot timers, LB-U11, 12, and 15. The Charge/Discharge
          timing sequence is initiated each time a trigger pulse
          (either AUTO or MANUAL) is generated. The trigger pulse
          (negative going) causes one shots U12 and U15 to
          activate. LB-U15 controls the charging interval while U12
          generates a delay to allow the charging relay ( HVRM-RL4)
          in the H.V. Mode to drop out. When a U12 completes its
          time out, U11 is triggered causing the actual output pulse
          discharge period to be generated. The timing sequence
          and nominal time duration for each one-shot period is
          shown in Figure 6.3. The high voltage discharges produced
          during normal operation do not interfere with the output
          pulse timing sequence. This circuit consists of components
          LB-Q17, 18 and 19.

                           Figure 6.3
                 Output Pulse Timing Sequence Relay Drivers

                 The drive signals required by the charge and discharge in
                 the HVRM are developed by relay drivers on the LB. Table
                 6.2 lists each driver and the relay it drives.

                          Table 6.2
        Charge/Discharge Relay and Driver Identification

Relay                Function & Type                             Driver
HVRM-RL4           H.V. Mode-Charge            (SPST)           LB-Q10
HVRM-RL5           H.V. Mode-Discharge         (SPST)           LB-Q15
 Charge/Discharge Indication

                  The GREEN CHARGE indicator (DRM-DS7) is illuminated
                  when the HBM storage capacitor is being charged by the
                  appropriate charging relays (see Table 6.2). This

           corresponds to the time when the output of LB-U15 is low
           (zero). The driver for this indicator is LB-U15.

           The AMBER DISCHARGE indicator (DRM-DS8) is
           illuminated whenever the discharge relay (HVRM-RL5) is
           activated and the Human Body Model capacitor is being
           discharged into the Device Under Test. The driver for this
           indicator is LB-Q15 which also drives the H.V. discharge
           relay. CHARGING VOLTAGE DPM and Scaling Networks

           This indicator is a 3 ½ digit LED display which indicates
           the level of the charging voltage being produced by the
           HVPS. Since the DPM is capable of displaying up to a
           maximum to +1999 volts D.C., it is necessary to scale
           down the high voltage levels produced by HVPS. This
           voltage scaling is performed in the HVRM by a divider
           network consisting primarily of a 100 megohm precision
           resistor (HVRM-R2) and several smaller precision
           resistors (HVRM-R3,4,5 and 6). A small reed relay
           (HVRM-RL3) is used to provide scale changing from the
           HI to LO Modes. Two (2) resistors are used for calibration
           purposes (HVRM-R4 and R6) in the HI and LO Modes

           A second attenuator network on the DPM is provided to
           allow the user to calibrate the CHARGING VOLTAGE
           Meter with the actual high voltage pulse produced and to
           compensate for output losses (if any). The front panel
           accessible Voltage Calibration Control (DPM-R3) allows
           for a reduction of the DPM indication by up to 50% of the
           true charging voltage level.   H.V. Relay Module

           The HVRM block in Figure 6.1 has been redrawn in Figure
           6.4 to better illustrate its function. The high voltage input
           from the HVPS is fed to the H.V. scaling network where it
           is scaled down for use by the CHARGING VOLTAGE
           Meter. A DPM output select signal drives a scaling relay
           (HVRM-RL3) to shift the level accordingly for the HI/LO
           Modes. The scaling relay is activated (contacts closed) in
           the HI Mode.

The high voltage charging current is limited by a limiting
resistor (HVRM-R1)   Charge/Discharge Cycle

             During the charging period, the Charge
             Relay (HVRM-RL4) is energized by a H.V.
             Mode charge relay drive signal causing the
             storage capacitor (HVRM-C4) to charge.
             The H.V. Mode Charge Relay then opens,
             and after a delay, the H.V. Mode Discharge
             Relay drive signal causes the H.V.
             Discharge Relay (HVRM-RL5) to close,
             applying the energy stored in the H.V. HBM
             storage capacitor to the output via the H.V.
             Mode Human Body Model resistor (HVRM-
             R8). After completion of the H.V. Mode
             discharge cycle, the Discharge Relay opens,
             the Charge Rely closes, and the H.V. HBM
             capacitor is recharged in preparation for the
             next discharge cycle.   HI/LO Voltage Mode Selection

              when the LO Voltage Mode is selected, a
              control signal (HVM=1) is sent to the HVPS
              which causes a scale change relay to open.
              This enables the correct DPM voltage
              range to be selected. In the HI Mode, this
              relay is closed, again selecting the proper
              voltage scaling for the DPM

                                          Figure 6.4
       Model 910 Electrostatic Discharge Simulator – High Voltage Relay Module

                       Low Voltage Power Supply

                                         The LVPS interfaces with the power line via the
                                         power transformer, T1. Its outputs provide
                                         both regulated and unregulated voltages which
                                         are used by the unit’s various sub-assemblies.
                                         Table 6.3 lists the outputs provided and the
                                         components associated with producing each

                                    Table 6.3
                               LVPS Components Table

Output Voltage       Output Test Point      Transformer             Components
                                            Input Points
Reg +5v                 E17                   E1, 2, 3              D 1&2, C1 &4, U1
Reg +12 (Relay)         E15                  E4, 5, 6               D3, D5, C2, C5, U2
Reg +12 (L)             E13                  E4, 5, 6               D3, D5, C2, C6, U3
Reg -12                 E12                   E4, 5, 6              D4, D6, C3, C7, U4
UnReg +32               E16                  E7, 8                  D7, C8, C9

All components on the LVPS are soldered-in. Repairs should be made
with the proper equipment and by qualified personnel only.

     High Voltage Power Supply

                       The variable L.V. section of the H.V.P.S. is a
                       series regulator whose output is determined by
                       the settings of the FINE and COARSE controls
                       (CP-R2, R1) and the status of the RPSD signal
                       (See section or The heart of
                       the series regulator is U1, and two (2) current
                       amplifiers, Q1 and Q2. Q1 is the high current
                       stage which is driven at a somewhat lower level
                       by Q2. Resistors R11 and R21 are used to
                       calibrate the maximum outputs of the supply in
                       the low voltage and high voltage modes

                       The output of the supply varies from zero to
                       +2.4 volts (nominal) in the LO Mode and 0 to
                       +12 volts (nominal) in the HI Mode. These
                       output voltages may be monitored at Terminal
                       E12. Transistor Q11 reduces the supply output
                       to zero when RPSD is a logic “1”. Q4 and Q5
                       program the output range of the supply as a
                       function of the mode selected. A logic “1” on
                       Terminal E28 programs the supply for the H.V.
                       Mode (supply output will be 0 to +12 volts).

                       The second functional block in this supply is the
                       gated drive stage which contains transformer T1
                       and transistors Q5, 6, 7, 8, and 9. Transistor
                       Q9 is an on-off gate which is controlled by the
                       remote shutdown signal (RSPD). It determines
                       the 13KHz oscillator circuit (T1, Q5, and Q6)
                       on/off status. The oscillator is on when Q9 is on
                       (in saturation). The secondary of T1 drives the
                       bases Q7 and Q8 which are the drivers for H.V.
                       step up transformer.

                       The third functional block is the multiplier and
                       polarity selection stage. Here, two (2)
                       independent X7 multipliers are employed, one
                       for each polarity. They each multiply the output
                       of T2 to the desired charging voltage level.

                                 Polarity selection is accomplished by the action
                                 of polarity select relays RL1, RL2 to select a
                                 positive output and relays RL3, RL4 to select a
                                 negative output. The drive signals for polarity
                                 selection are on terminals E30 and E31 for the
                                 positive and negative modes respectively. A low
                                 signal (0 volts) on a given terminal signifies the
                                 selection of that mode (e.g. “0” volts on E30
                                 when a positive polarity output has been

6.3    Trouble Shooting and Repair

      This paragraph covers some of the possible failure modes and provides a
      table which should aid repair personnel in locating the faulty components.
      Partial disassembly of the housing is also covered.

      1. Because of the high voltage present in this unit, extreme care must be
         exercised when working on the unit with its cover removed. Failure to
         use reasonable care can result in serious injury to personnel and/or
         damage to the equipment.

      2.    To protect the CHARGING VOLTAGE DPM against high voltage
           transients which may occur with the cover removed, it is recommended
           the DPM be disconnected during trouble shooting.

           6.3.1 Removal of Top and Bottom Covers

           Top Cover Removal

                            To gain access to the LB, LVPS, DPM, and the
                            HVRM the top cover must be removed. To
                            accomplish this, remove the four (4) flat head screws
                            (two on the right side and two on the left side) that
                            secure the cover to the frame. Slide the cover off by
                            lifting slowly in the vertical direction.

           Bottom Cover Removal

                            To gain access to the CP and the underside of the
                            HVPS, it will be necessary to remove the bottom
                            cover. To accomplish this, first remove the three (3)
                            screws located on the underside of the unit directly
                            below the front control panel. Two (2) of the three (3)
                            screws will be in the center of each of the two (2)

                          rubber bumpers. With the unit in its normal
                          (horizontal) position, remove the four (4) flat head
                          screws on the sides of the unit (two on the left side
                          and two on the right). Lift the unit vertically by
                          holding the rear panel and the front edge of the front
                          of the panel. The frame will separate from the bottom
                          cover. Place the frame on a suitable surface for

        6.3.2 Trouble Shooting Guide

               Listed in Table 6.4 are some of the possible faults which may
               occur, their most probable causes and recommended actions to
               take to correct the fault. Most repair actions listed involve the
               replacement of plug-in components. If the fault requires
               replacement of a soldered-in component, the repair should be
               made by a qualified person using the proper equipment. If this is
               not possible, it is recommended that the unit be returned to
               Electro-Tech Systems, Inc. for repair.

                     Before proceeding with detailed trouble shooting, fault
                     location , and/or replacement of components, remove the
                     top (and bottom) cover(s) and perform a visual
                     inspection of all internal P.C. boards and cables. Check
                     to see that all cable plugs are properly seated in their
                     respective sockets and that all plug-in integrated circuits
                     are fully seated. A loose connector or IC can cause the
                     system to malfunction.

6.4   Internal Adjustments

      6.4.1   High Voltage Power Supply Output and DPM Calibration

              There are only two (2) adjustments provided on the HVPS board.
              These adjust the maximum output of the supply in each of the two
              (2) modes. HVPS-R21 adjusts the output of the HI Mode and
              should always be adjusted before R11, which calibrates the output
              in the LO Mode.

              Be sure power is OFF and the High Voltage FINE and COARSE
              controls are both fully counter clockwise before removing the
              cover or attempting to do any work on the HVPS. Disconnect
              the DPM connector to avoid damage if an arc is drawn during
              these tests.

                                   41   High Voltage Mode Charging Voltage Level Calibration

          Connect a high voltage measuring instrument with an
          input resistance in excess of 1,000 megohms and an
          input voltage rating of at least 10,000 volts D.C. to the
          output of the HVPS. Remove the CAPACITOR module
          from the OUTPUT panel which is the red 0.80” pin jack.
          See Figure 6.5.

          Set the High Voltage Voltmeter to a scale that will enable
          10,000 volts to be measured. Place the RUN/HOLD
          button in the HOLD (down) position, the POLARITY
          button in the (+) position, the VOLTAGE Mode button in
          HI, turn on the AC power and place the H.V. ON/OFF
          button in the ON position. Rotate the FINE voltage
          control so that it is at its approximate mid-position
          (pointer at 12 o’clock). Set the COARSE control until it is
          fully clockwise. While observing the H.V. Voltmeter
          reading, rotate the High Voltage calibrate resistor
          adjustment (HVPS-R21) screw until the meter reads
          8,250 volts.


FAULT or MALFUNCTION                         SUSPECT BOARD and/or COMPONENT        ACTION

1. Nothing works-DPM and lights do           1. Check line cord and main AC fuse   1. Test/Replace if bad.
    not illuminate-relays do not activate.   2. LVPS - Main power transformer      2. Test/Replace if bad.

2. All indicators work properly but none     1. LVPS - U2                          1. Check LVPS test terminal
of the relays activate.                                                               E15. If no +12 volts is present,
                                                                                      replace U2.

3. No discharge pulse is produced but        1. HVRM - Faulty RL5                  1. Check Relay coil and replace if open.
   CHARGE/DISCHARGE indicators
   work properly.                            2. HVRM - Open R1                     2. Test for proper resistance, replace
                                                                                    if necessary.
                                             3. HVRM - Faulty or improperly        3. Check for proper mounting-or
                                                mounted C4                              replace if faulty.

4. No discharge pulse and DISCHARGE           1. LB-Q15                            1. Q15 bad-replace.
   light does not flash.                      2. LB-U11                            2. Check U11-replace if bad.

5. Charging Voltage DPM provides proper       1. LB-U13, U14                       1. Replace U13 and/or U14 as required
   H.V. readout but H.V. ON light does not                                            to restore proper operation.
   come on when H.V. is present.              2. DRM-DS4                              2. LED bad-replace.
                                              3. LB-Q2                             3. Q2 bad- replace.

6. H.V. ON indicator stays on even with       1. LB-U13, 14                        1. Same as above.
   H.V. switch in OFF position.


7. HI/LO Mode select does not function.      1. LB-U8                         1. U8 bad-replace.
   Indicator lamp indication does not        2. CP-S3                         2. S3 bad-replace.

8. HI or LO indicator lamp stays on when     1. LO lamp stays on: LB-Q4       1. Q4 bad-replace.
   opposite mode is selected.                2. HI lamp stays on: LB-Q6       2. Q6 bad-replace.

9. Polarity mode select does not function.    1. LB-U9                        1. U9 bad-replace.
   Indicator lamp indication does not change. 2. CP-S4                        2. S4 bad-replace.

10. + or – lamp stays on when opposite        1. +lamp stays on: LB-Q7        1. Q7 bad-replace.
    polarity is selected.                     2. –lamp stays on: LB-Q8        2. Q8 bad-replace.

11. HOLD button does not stop discharges      1. CP-S7                        1. S7 bad-replace.
    from being produced.

12. HOLD button stops output pulse, but       1. CP-S7                        1. S7 bad-replace.
    unit continues to count in AUTO mode.     2. LB-U1                        2. U1 bad-replace.

13. CHARGING VOLTAGE DPM reads zero            1. DPM                         1. Test DPM and
    when H.V. button is ON and FINE and                                           replace if faulty.
    COARSE controls are turned clockwise.      2. HVRM-R2, R3, R4, R5, R6     2. Check H.V. divider for open
    Normal H.V. output pulse is produced                                         resistor and replace if faulty.
                                               3. DRM-R2, R3                  3. Check resistors for open circuit.
                                                                                 Replace if faulty.

14. Charging Voltage DPM reading               HVRM-RL3                       1. Test and replace if defective.
    Is about 1.5X too high in the HV mode.

FAULT or MALFUNCTION                           SUSPECT BOARD and/or COMPONENT   ACTION

15. Charging Voltage DPM flashes 1999          1. DPM                           1. DPM defective - replace.
    with H.V. off.

16. Indicator lamps do not light but unit      DRM-DS2, 3, 4, 5, 6, 7, 8        1. LED indicator
    functions properly.                                                            lamp is defective - replace.

17. No H.V. output-                            1. HVPS-U1                       1. Replace.
    a. H.V. button ON and controls set for     2. HVPS-Q1                       2. Bad-replace.
    b. H.V. output.                            3. CP-S2                         3. Test-if open, replace.
    c. DPM is functioning properly and reads
       zero.                                   4. LB-U10                         4.   Replace.
                                               5. HVPS-Q11                       5.   Replace.
                                               6. HVPS-Q10                       6.   Replace.
                                               7. HVPS-Q9                        7.   Replace.

18. H.V. output does not go to zero when       1. HVPS-U1                        1. S7 bad-replace.
    FINE and COARSE controls are fully CC      2. HVPS-Q2                        2. Replace.
                                               3. HVPS-Q1                        3. Replace.
                                               4. CP-R1, R2                      4. Test-replace if defective.

19. AUTO MODE-Indicator does not               1. LB-U                           1. Replace.
    light in AUTO MODE.                        2. DRM-DS1                        2. Replace.
                                               3. CP-S6                          3. Check and
                                                                                    replace if bad.

20. AUTO MODE Indicator does not                 1. LB-U6                       1. Replace.
    reset to zero when RESET button is          2. LB-U3                        2. Replace.
    depressed.                                  3. CP-S1                        3. Check and replace if bad.


21. AUTO MODE – unit does not start           1. LB-U7, U1, U4, U5, Q1         1. Replace in order shown
    when DISCH button is depressed.                                               until proper operation is
    DISCHARGE light does not light.                                               restored.

22. AUTO MODE- DISCHARGE light comes           1. LB-U7, U3                    1. Replace in order shown
    on but AUTO MODE counter does not                                             until operation Is restored.
    display count other than zero.

23. AUTO MODE- pulses are produced and         1. LB-U1                        1. Replace.
    unit counts normally, but does not stop    2. CP-S5                        2. Test and replace if bad.
    when count on DISCHARGES selector
    is reached.

                                                              46   Charging Voltage DPM Calibration HI Mode

          Follow the procedure in the preceding paragraph then,
          after adjusting the output of the HVPS via HVPS-R21,
          adjust the High Voltage Mode DPM calibrate resistor
          (HVRM-R4) until the DPM reads +8.25 kV.

                      Figure 6.5
  High Voltage Power Supply – H.V. Test Point Location

          Calibration    of   the   DPM    must     be     done
          with the front panel CAL adjustment turned to its fully
          clockwise position.   LO Voltage Mode Charging Voltage Level Calibration

          Follow the basic set-up procedure outlined in
          above except set the VOLTAGE Mode button to LO, then
          set the High Voltage ON/OFF switch to ON. Select a
          scale on the High Voltage Voltmeter such that 2,000 volts
          can be accurately read. Adjust the LO Voltage Mode
          calibrate resistor (HVPS-R11) adjustment screw until the
          High Voltage Voltmeter reads 2,000 volts D.C.

                    47    Charging Voltage DPM Calibration/Low Mode

                    Follow the procedure above (, then reduce the
                    settings of the FINE and COARSE control until the High
                    Voltage Voltmeter reads +1,900 volts. Adjust the LOW
                    Voltage DPM cal resistor (HVRM-R6) until the DPM reads
                    1,900 volts.

                    Performance of the Calibration procedures in
                    through above, using a precision H.V. Voltmeter,
                    will insure that the proper high voltage charging levels will
                    be produced by the HVPS and that the DPM will indicate
                    the proper levels. Calibration of the output discharge
                    pulse should also be performed to verify both the pulse
                    level and wave shape. The Voltage CAL adjustment may
                    then be used to increase the stored voltage level relative
                    to the DPM indication to compensate for possible losses
                    in the output cabling and load (See 4.0 for output pulse
                    shape and amplitude verification).

6.4.2     Output Pulse Timing Sequence Calibration

          Covered in this paragraph is the procedure to be followed to verify
          and/or adjust the timing of the three (3) delay timers on the Logic
          Board (LB-U11, 12 and 15). The proper timing for these three (3)
          circuits is shown in Figure 6.3.

     Initial Set-Up, Oscilloscope Synchronization and
                      Calibration of LB-U12

                      With the AC power OFF, remove the top cover of the
                      Discharge Simulator and locate the logic board. Locate
                      U12, the integrated circuit timer that generates the
                      Initial Delay Time shown in Figure 6.3, and connect its
                      output (U12-Pin 3) to the Channel-1 input of a dual
                      trace oscilloscope with a calibrated time base and the
                      ability to sync to the vertical Channel-1 input.

                      A “Dip-Clip” (Pomona Electronics) or equivalent IC test
                      interface device is recommended for securing the
                      scope test probe to the IC timer. The output pulse to
                      be observed will be positive going with a nominal
                      amplitude of +4 volts and a period of 100 milliseconds.
                      Turn on the AC power and, while depressing the
                      DISCHARGE button with the H.V. OFF and the Mode

          set for MAN, adjust the scope to sync to the positive
          edge of this pulse. A sweep speed of 20 msec/cm is
          recommended. Measure the pulse width and, if
          necessary, adjust R28 until the observed pulse width is
          100 +10 milliseconds.   Calibration if U11, Discharge Pulse Width

          Follow the procedure outlined in Then connect
          the Channel-2 input of the dual trace scope to U11-pin
          3. While still synchronizing the scope to the positive
          going edge of U12-pin 3, observe and measure the
          output pulse width of U11, pin 3 on Channel-2. A
          sweep speed of 50MS/CM is recommended. If
          necessary, adjust R25 to achieve a pulse width of 200
          +10 milliseconds.   Calibration of U15, Charge Relay Timing

          Follow the procedure in, then connect the
          Channel-2 scope input to U15-pin 3. Synchronize the
          scope to the Channel-1 input, U12-pin 3 (positive
          edge). Using sweep speed of 0.1 sec/cm, observe and
          measure the output pulse width of U15-pin 3. If
          necessary, adjust R39 such that the pulse width is 650
          +20 milliseconds.   Final Check of Timing Sequence

          Using the dual trace capability of the oscilloscope in the
          “chopped” mode, and synchronizing to the positive
          going edge of LB-U12-pin 3, use the Channel-1 and 2
          scope inputs to verify that the outputs of U12, 11 and
          15 (pin 3) correlate with Figure 6.3 with respect to
          timing relationship and pulse widths. If all
          measurements agree with Figure 6.3, the timing
          sequence is correct and no further adjustments are
          necessary. If the measurements are not correct, repeat
          the procedures in, and and then
          re-check all timing against Figure 6.3.

                                    Figure 6.6
                              HBM Plug-In RC Networks

6.5   Human Body Model Values

      The Model 910 Electrostatic Discharge Simulator is supplied with the Human
      Body Model capacitor and resistor values that result in a capacitance and
      resistance at the output jack of 100pf +10% and 1,500 ohms +2%

      6.5.1   Changing the Capacitor and Resistor

              The capacitor and resistor are plug-in modules located on the front
              OUTPUT Panel as shown in Figure 6.6. To change values, simply
              remove the capacitor and resistor modules by pulling them out of
              the panel. Both modules are connected to the output network via
              0.80” pin jacks.

              The capacitor module can be opened by unscrewing the brass
              thumb screw to add additional capacitors.

              The 100 pf capacitor module contains capacitors whose value,
              when added to the intrinsic capacitance of the discharge relay will
              result in 100 +10pf being measured at the output terminal. Most

              910s have an intrinsic capacitance of 100 pf, hence the
              capacitor module will not contain any additional capacitors.

              Before removing the capacitor module, connect the output to
              ground and initiate the DISCHARGE button several times to ensure
              that the capacitor is fully discharged.

6.6   Line Voltage Selection

      The Model 910 can operate from line voltages of 100, 110, 220 and 240
      VAC, 50/60Hz. The correct line voltage is selected using the LINE
      VOLTAGE selector module located on the rear panel of the unit.

      For line voltage of 100 or 110 volts a ¾ amp Slo-Blo 3AG fuse should be
      used. For line voltages of 220 or 240 volts a 3/8 amp Slo-Blo 3AG fuse
      should be used.

      6.6.1   Sub-Assembly Location

              Figure 6.7 is a top view of the Model 910 Electrostatic Discharge
              Simulator. Shown are the board assembly locations as well as the
              calibration resistors on each board.

      6.6.2   Interconnect Information

              Figure 6.8 is a diagram which shows how the various sub-system
              assemblies are interconnected. The balloon associated with each
              cable shows the number of conductors in each cable. Care should
              be taken when re-connecting cables, since failure to insert a given
              cable into its proper socket and/or failure to orient the cable plugs
              properly can result in a system malfunction and/or component
              failure. Pin #1 is the Brown wire and is designated by a Black Dot
              on both the cable and the board.

     Figure 6.7
P.C. Board Location

        Figure 6.8
Sub-System Interconnection


   Electro-Tech Systems, Inc. warrants its equipment, accessories and parts of its manufacture to
   be and remain free from defects in material and workmanship for a period of one (1) year from
   date of invoice and will, at the discretion of Seller, either replace or repair without charge,
   F.O.B. Glenside, similar equipment or similar part to replace any equipment or part of its
   manufacture which, within the above stated time, is proved to have been defective at the time it
   was sold. All equipment claimed defective must be returned properly identified to the Seller (or
   presented to one of its agents for inspection). This warranty only applies to equipment
   operated in accordance with Seller’s operating instructions.

   Seller’s warranty with respect to those parts of the equipment which are purchased from other
   manufacturers shall be subject only to that manufacturer’s warranty.

   The Seller’s liability hereunder is expressly limited to repairing or replacing any parts of the
   equipment manufactured by the manufacturer and found to have been defective. The Seller
   shall not be liable for damage resulting or claimed to result from any cause whatsoever.

   The warranty becomes null and void should the equipment, or any part thereof, be abused or
   modified by the customer of if used in any application other than that for which it was intended.
   This warranty to replace or repair is the only warranty, either expressed or implied or provided
   by law, and is in lieu of all other warranties and the Seller denies any other promise, guarantee,
   or warranty with respect to the equipment or accessories and, in particular, as to its or their
   suitability for the purposes of the buyer or its or their performance, either quantitatively or
   qualitatively or as to the products which it may produce and the buyer is expected to expressly
   waive rights to any warranty other than that stated herein.

   ETS must be notified before any equipment is returned for repair.            ETS will issue an
   RMA(Return Material Authorization) number for return of equipment.

          Equipment should be shipped prepaid and insured in the original packaging. If the
   original packaging is not available, the equipment must be packed in a sufficiently large box (or
   boxes is applicable) of double wall construction with substantial packing around all sides. The
   RMA number, description of the problem along with the contact name and telephone number
   must be included in formal paperwork and enclosed with the instrument. Round trip freight and
   related charges are the owner’s responsibility.




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