Trouble Shooting Guide, Advanced
4/00021-3/FEA 209 544/25 C
Ericsson Mobile Communications AB
61(78)
Power up the board and start it in EFRA with the test program.
Go to Audio / Audio.
Start ATMS – PCM – AFMS.
An appropriate signal for ATMS is 1kHz, 100mVrms or 280mVp-p sinus.
Attach the signal to X800: 11.
Check if the signal exists at N500 (X510 the test-point close to V503).
If the signal is missing at N500 (X510), the fault mostly is due to N501.
But it can also be due to N500.
The reference voltages at N500 should also be measured, they should be:
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
N501, 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.
17.6 The AFMS output part is out of order
When the AFMS output part is out of order it is only the audio paths “Mic – AFMS”, “ATMS
– PCM – AFMS” and “ATMS – CPU – AFMS” 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 is not oxidised or burned, and that the system connector pins
are correctly soldered.
Power up the board and start it in EFRA with the test program.
Go to Audio / Audio.
Start ATMS – PCM – AFMS.
An appropriate signal for ATMS is 1kHz, 100mVrms or 280mVptp sinus.
Attach the signal to X800: 11.
Check if the signal exists at N500 (X510 a test-point close to V503).
If the signal is missing at N500 (X510), the fault mostly is due to N501. But it can also be due
to N500.
Check the signal at C508, if its missing the fault probably is due to N500.