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21.7 The CPU loops are out of order
When the CPU loops are out of order is it only the audio paths "ATMS – CPU – AFMS" and
"Mic – CPU – Earphone" that are faulty.
The other three should work.
Open the phone and check for liquid damages.
No further action should be taken for a liquid damaged telephone.
The fault is usually due to D600, but sometimes D900.
The fault can also be due to a faulty component, but usually is it due to bad soldering.
21.8 Both the CPU loops and the PCM loops are out of order
When the CPU loops and the PCM loops are out of order is it only the side tone paths,
"ATMS – Earphone" and "Mic – AFMS", that are working.
Open the phone and check for liquid damages.
No further action should be taken for a liquid damaged telephone.
Give the board power and start it in the test program.
Check the feed voltage VDSP (+3.2 V
If the feed voltages are correct, make sure R904 has not fallen of.
If the resistor is mounted and got correct resistance, the fault usually is due to N800, but
sometimes is it due to D600, D900 or its soldering.
If the feed voltage are too low, measure the resistance of VDSP and VDSPC to ground (>25
Kohms).
If the resistances are correct, replace the regulator N701 for VDSP or V703 for VDSPC.
If the resistance is too low, use the schematics.
Remove one component (or lift the pin/pins feeding the circuit) at the time that is fed from the
short circuit voltage and measure the resistance after removing it.
You have found the faulty component when the resistance is raising after removing.
Don't forget to mount all the components that have been removed.
You also should replace the circuits on which you lifted the pins.
The short circuit is usually due to D900 or anyone of C900, C902-C906.
If the feed voltages are too high, replace N701 respectively V703.
21.9 The Speaker mode part is out of order
When there is a speaker mode fault is it 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, and the
earphone part is working, but the fault remains, so then the fault is at the speaker amplifier.
Open the phone and check for liquid damages.
4/00021-3/FEA 209 544/18 B
) and VDSPC (+2.5 V
DC
Trouble Shooting Guide, Advanced
).
DC
93(121)
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