Rtc - Ericsson GF 768 Troubleshooting Manual

Troubleshooting guide

1. RTC

1.1 Find the fault.
Start the phone with a SIM-card and a fully charged battery inserted. Set the correct time. Remove the battery and
reinsert it after a minute.
• If the clock says 00:00, go to 1.2.
Compare to the correct time.
• If the clock is speeding or if it is halted, go to 1.3.
The component side of the circuit board is shown in fig. 1.1.
1.2 The phone shows 00:00 after removing and reinserting the battery.
Open the phone and make sure that the backup capacitor, C720 (class A, fig. 1.2), is correctly soldered.
If it is, replace it. Assemble the phone, start it up and set the correct time. Wait a few minutes for the capacitor to
charge. Remove the battery and reinsert it after a minute. Check that the fault is fixed (the backup capacitor needs
6
Fig. 1.1
Fig. 1.2
4/00021-2/FEA 209 544/6 C