Backup Battery Troubleshooting - Nokia 6120 classic Service Manual

RM-243
BB Troubleshooting and Manual Tuning Guide

Backup battery troubleshooting

Verify that the backup battery is empty (U<1V). Switch the phone on. Measure voltage of the battery when
the main battery is connected to the phone and the phone is switched on.
Wait a few minutes and monitor that the backup battery voltage rises. Switch off the phone, disconnect the
main battery and monitor that the voltage of the backup battery decreases. Normal behaviour of the voltage
is described in the figures below.
Figure 8 Charging backup battery
Figure 9 Discharging backup battery
If the voltage rises and falls quickly, check whether G2200 or C2242 is broken or short-circuited. Backup
battery can be also dead. If the voltage stays ~0V, check resistance VBACK against GND. If there is no short-
circuit, AVILMA is faulty. Replace AVILMA.
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