Huawei P20 - Contacts; Managing Business Cards

EML-L29V100R001 Advanced Maintenance Manual V2.1
INTERNAL
2019-6-25
Huawei Confidential
Page 40 of 67
4.10 Receiver Failure
4.10.1 Maintenance Process
Receiver failure
Is the receiver
resistance normal (about 30
ohms)?
Replace the receiver.
Send the faulty receiver
to the manufacturer for
analysis
There is
no sound or
the sound is
too low
Noise
The receiver
foam is not in
position. Install
it again
No
Perform cross
verification. Is the PCBA
normal?
Yes
Are
EARN and EARP
short-circuited to the ground?
Is the circuit open-
circuited?
Ask PCBA process
engineers to
analyze the cause
It is suspected that
Codec U2201 is
faulty. Replace U2201
Use an
X-ray machine for the
check. Do L2502 and L2503
have soldering
issues?
Yes
Yes
No
No
No