45
Service Manual
7-12
7-18. Calibration
The Battery Pack Option is adjusted at the factory for optimum performance and should
not require adjustment when installed. However, if either of the two adjustment pots on
the top of the Battery Pack Option circuit assembly have been turned inadvertently, or if
the unit has been repaired, the following procedure can be used to reset the controls for
optimum battery life and proper power supply system performance.
The following equipment is needed to perform these adjustments:
• An 1800 Ω, 1/2 watt, 5% resistor
• A voltmeter
The following steps describe how to adjust the Battery Pack Option:
1. With the Battery Pack Option installed in the meter and with the meter disconnected
from line power, unplug the battery connectors from the battery + and - terminals
(Figure 7-6).
2. Install the 1800 Ω resistor across the battery pack connectors.
3. Connect the meter to line power and turn the meter ON.
4. Connect the test leads from another voltmeter across test points TP1 and TP2 on the
Battery Pack Option circuit assembly (as shown in Figure 7-7). Adjust the front
potentiometer (R39) (top of the Battery Pack Option circuit assembly) until the
voltmeter across the test points reads 9.25 V.
5. Turn the meter OFF.
6. Connect the test leads from another voltmeter across TP1 and TP2 on the battery
pack option circuit assembly. Adjust rear potentiometer R20 (top of the battery pack
option circuit assembly) until the voltmeter across the test points reads 9.35 volts.
(With the meter connected to line power and turned off, the charging voltage reads
approximately 9.35 volts.)
7. Disconnect the line cord from the meter.
8. Remove the 1800 Ω resistor, and plug the battery pack connector wires back into the
battery pack (the red wire to + and the black wire to -.)
9. To ensure the battery pack connector wires are properly connected and the battery
kit is properly installed, turn the meter ON without plugging in the power cord.
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