Teledyne LeCroy AP034 - Manual (Page 45)

Operator’s Manual
922261-00 Rev A 39
B. Adjust Fine DC Balance (R304)
1. Remove the shorting plug from the Logic Board.
2. Reinsert the shorting plug into the two holes near the end of the Logic Board. (Figure 8.)
3. Reenter Cal Mode by pushing either of the two buttons that protrude through holes in the
Logic Board.
4. ,Remove the BNC cable from the precision 50 Ω terminator connected to the DMM.
5. Short the output BNC connector by reconnecting the cable to the SHORT connector on the
AP033/AP034 Calibration Fixture. The SHORT connector is the only BNC connector on the
AP033/AP034 Calibration Fixture that does not have corresponding input pins for the probe
tip. It is located on the end of the board beyond the Common Mode Terminated connector.
6. In Cal Mode, the EFFECTIVE GAIN indicators serve as an adjustment indicator. The
EFFECTIVE GAIN indicators are located on the Logic Board (Figure 8). It may be necessary to
hold the boards in your hands to see the indicators while making the adjustment.
7. Using a low capacitance screwdriver, adjust Fine DC Balance (R304) until the

10 EFFECTIVE
GAIN indicator lights (Figure 10).
Figure 10, ÷11Effective Gain Indicator
8. Disconnect the BNC cable from the short connector.