Rtc (Real Time Clock) - Ericsson I 888 Trouble-Shooting Instruction

I888, Standard Electrical Repairs

10 RTC (Real Time Clock)

10.1 Find out what kind of fault it is.
Start the phone with a Sim card and a fully charged battery. Set the clock for correct
time. Remove the battery and connect it again after one minute.
• If the clock on the phone shows 00:00, proceed to section 10.2.
• Compare the time with a clock that is correct. If the clock on the phone is speed-
ing or is on hold, proceed to section 10.3.
10.2 The clock shows 00:00 after removing the
battery.
Open the phone and check the solderings on the backup capacitor C720 (class A,
Fig 10.1).
Fig. 10.1
C720
If the solderings are fine, replace it. Put the phone back together, start it and set the
correct time again. Wait a few minutes to allow the backup capacitor to be enough
charged. Remove the battery and put it back on after one minute. Make sure the
fault is gone. (The backup capacitor needs to be charged a couple of hours to be
fully charged.) Compare it with a correct time. If the clock on the phone is speeding
or is on hold, proceed to section 10.3.
10.3 The clock is speeding or on hold.
Open the phone and check the solderings on D600:117-118 (Fig 10.2). Check the
solderings on the crystal B600 also. If they are fine, replace B600 (class A, Fig
10.2). Put the phone back together and compare the clock with a correct time. If that
didn´t make it, replace C690 (class A, Fig 10.2) and C691 (class A, Fig 10.2).
Check the clock again, if the fault remains replace D600 (class A, Fig 10.2).
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