Zero Adjust; Section Iii. Operation Procedures; Example Of Non-Destruct Mode Testing - Unitek MICROPULL IV MP4/115 Operation And Maintenance Manual

CHAPTER 3: OPERATING INSTRUCTIONS
6 When the HOOK RETURN switch is set to AUTO, the hook automatically slews to the Downstop in
the event that any of the End Of Test conditions is met.

Zero Adjust

1 On the rear of the Electronic Control Unit, set the ZERO switch to MAN (out).
2 Slowly turn the zero adjust potentiometer (R6) (figure 3-4) on the beam clockwise using the insertion
tool screwdriver until the PEAK FORCE indicator minus sign just lights.
3 Turn the zero adjust potentiometer (R6) counterclockwise until the PEAK FORCE indicator minus sign
barely extinguishes. Ignore the displayed digits as they will not change. The beam amplifier output is
now zero.
4 Press the footswitch and note that the PEAK FORCE display reads 000.
5 Pull down, gently, on the hook. Release it, then press the FT SW ENABLE switch followed by the
footswitch. The display should re-zero.
6 Turn the zero adjust potentiometer (R6) until the display reads 003.
7 On the rear of the Electronic Control Unit, press the ZERO switch in (AUTO). Notice that the display
automatically zeros after each simulated test.
NOTE: The reason for setting the amplifier three counts positive is that negative readings cannot be read
and, therefore, cannot be automatically corrected. Three counts compensates for the drift which normally
occurs during warm-up.
In the AUTO ZERO MODE the MP4 display reads the net force applied to the wire bond EXCEPT when
the Minus Sign is lit.

Example of Non-Destruct Mode Testing

You are now ready to apply 2 gf to the wire bond. In the case of the 1000 gf beam the force will be 200 gf.
1 Place the MODE switch to NON-DESTRUCT and the HOOK RETURN switch to MANUAL. On the
rear of the Electronic Control Unit, set the ZERO switch to MAN (out).
NOTE: In normal operation, when you work in the Manual Zero Mode the MP4 should be zeroed. But, for
the purpose of this illustration it is not necessary.
2 Use your left hand to manipulate the device holder and your right hand to operate the Control Lever.
Press the footswitch, signaling the MP4 that you are ready to start the test. The red Test Status Indicator
will light.
3 Move the hook, as necessary, in order to position it under the wire bond.
4 Raise the Control Lever. The hook will track the movement of the Control Lever until the PRESET
FORCE is applied to the wire bond, 2 gf less 3 counts, in this case. The Test Status Indicator will go out
3-6
Section III: Operation Procedures
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MICROPULL IV WIRE BOND PULL TESTER
990-180