Trouble Shooting Guide, Advanced
4/00021-3/FEA 209 544/25 C
Ericsson Mobile Communications AB
60(78)
DEC 2 /1.2 V
DC
(C511), DEC 3 /1.7 V
DC
(C510) and REXT 1.2 V
DC
(R507),
if not try to resold the components or replace them depending where the fault is.
If all of the actions above have been done and the conclusion is made that some of the circuits
N500, D600 or D500 is faulty, a self-test of the phone in EFRA could be useful to determine
which of the circuits that could be faulty.
17.4 The earphone part is out of order
When there is an earphone fault it is only the audio paths “AFMS – Earphone” and “Mic –
CPU – Earphone” that is faulty.
The other three audio paths should be working.
The trouble shooting below assumes the earphone of the phone has been replaced, but the
fault remains, so then the fault is at the board.
Open the phone and check for liquid damage.
No further action should be taken for a liquid damaged unit, send it on according to the
local company directives.
Make sure the earphone springs at the dome-foil is correctly soldered, undamaged and not
dirty, also check the elastomer.
Measure the resistance between N500 (C514) – X850: 12 and N500 (C515) – X850:11 (both
0.0 ohm).
If the resistance is too large, it can be due to a foil damage.
If the resistance is correct, the fault probably is due to N500, D600 or D500 and their
soldering.
The reference voltages at N500 should also be measured:
DEC 2 should be 1.2 V
DC
(C511), DEC 3 should be 1.7 V
DC
(C510)
and REXT should be 1.2 V
DC
(R507).
If not, try to resold the components or replace them depending where the fault is.
If all of the actions above have been done and the conclusion is made that some of the circuits
N500, D600 or D500 is faulty, a self-test of the phone in EFRA could be useful to determine
which of the circuits that could be faulty.
17.5 The ATMS input part is out of order
When the ATMS input part is out of order it is only the audio paths “ATMS – PCM –
AFMS”, “ATMS – CPU – AFMS” and “ATMS – Earphone” that are faulty.
The other two should be working.
The trouble shooting below assumes the system connector of the phone has been replaced, but
the fault remains, so then the fault is at the board.
Open the phone and check for liquid damage.
No further action should be taken for a liquid damaged unit, send it on according to the
local company directives.
Make sure the system connector pads not is oxidised or burned.
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