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Trouble Shooting Guide, Advanced
21.11 All audio paths are working in EFRA, but both the
microphone and the earphone is out of order during a
connected call
If any of the signals EXTAUD or PORTHF is too low, short circuit against ground, the phone
thinks there is a hands free unit connected and switches the audio paths to the system connector
instead of the microphone and earphone of phone.
This is only valid during a connected call with signal program, or the signal part of the test pro-
gram, in the phone.
At this type of fault all audio paths will work with test program in EFRA.
Open the phone and check for liquid damages.
No further action should be taken for a liquid damaged telephone.
You must apply a DC signal +2.7 V
/ +3.2 V
at J602: 3, 5.
DC
DC
Apply the signal with a Hands free unit or zero ohm probe
Give the board power and start it in the test program.
Measure the voltages at J602: 3, 5 (+2.7 V
/ +3.2 V
).
DC
DC
If the voltage is low at anyone of them, the fault usually is due to a short circuit caused by dirt
around F600 and F602.
Clean them using alcohol and a brush.
The fault can also be due to a short circuit in F600 and F602, a break in R635 or R636 or an
incorrect VDIG.
If both voltages are correct, the fault can be due to D600, N800, D900 or its soldering.
4/00021-3/FEA 209 544/18 B
95(121)
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