User 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 9 Charging backup battery

Figure 10 Discharging backup battery

If the voltage rises and falls quickly, check whether G2200, C2238 or C2245 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.

RM-244

BB Troubleshooting and Manual Tuning Guide

Issue 1 COMPANY CONFIDENTIAL Page 3 –11