Huawei YU220 Service Manual page 54

Fault 4: plug in your headphones, there are tips, but the headset MIC invalid
Repair process: First, replacement headphones headset monomer exclude issues such
as the problem itself is not a headset, insert the headset call state when speaking on
the MIC signal voltage measuring MICBIAS1 whether 2V, the
measure whether MICP signal if AU_VIN1_N / P a signal, it indicates that the U501 Weld
FM
1.17
Schematic diagram:
2013-10-18
YU220 service manualV1.0
First
insert the
ear
And play
HPLP\HPRP
Whether
？
has
signal
Y
measureC802 、 C803
Whether has
？
signal
Y
measureR801 、 R802
Whether has
？
signal
Y
measureB 801 、 B 802
Whether has
？
signal
Y
Replace earphone
connector
Huawei secrets, no dispersion without permission
Reweld or
N
replace
CPU
Reweld or
N
replace
、
C802 C803
Reweld or
N
replace
R801 、 R802
Reweld or
N
replace
B 801 、 B 802
OK
；
case of 2V, then
。