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If the resistance is correct, the fault usually is due to N800 or its soldering, but in some cases it
can be due to D600.
If the resistance is too low, the fault probably is due to C851, but it can also be due to N800.
If the voltage at the middle circuit board pad of the microphone, X830: 1, is too low the fault is
due to N800, its soldering, a break in R812 or R814, a short circuit in C814 or maybe a foil
damage.
If all three voltages are correct, the fault is in the signal path of the microphone.
The levels of the signal (5 mV) are so low it is hard to follow the signals, MICP and MICN,
from the microphone to the inputs of N800.
If the resistors R810 and R811 haven't fallen of, the fault usually is due to a break in C818 or
C819.
The fault can also be due to N800 or its soldering.
21.4 The Earphone part is out of order
When there is an earphone fault is it the audio paths "AFMS - Earphone" and "Mic – CPU –
Earphone" that are 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 damages.
No further action should be taken for a liquid damaged telephone.
Make sure the earphone connection (J900) pogo pins is correctly mounted, undamaged and not
dirty.
Give the board power and start it in the test program
Make sure there is VANA at N901 pin1, and that I2CDAT, I2CCLK is ok.
Measure the resistance between N800: 26 and R906 zero ohm, between R914 and
R905 zero ohm, between R905 and J900: 1 zero 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 N800, N901 or its soldering.
21.5 The ATMS part is out of order
When the ATMS part is out of order is it only the audio paths "ATMS – PCM – AFMS",
"ATMS – CPU – AFMS" and "ATMS – Earphone" that is 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 damages.
No further action should be taken for a liquid damaged telephone.
Make sure the system connector pads are not oxidised or burned.
Give the board power and start it in the test program.
4/00021-3/FEA 209 544/18 B
Trouble Shooting Guide, Advanced
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