Speaker Failure; Aintenance Process; Maintenance Principle - Huawei P20 Maintenance Manual

4.11 Speaker Failure

4.11.1 aintenance Process

Speaker failure
(automatic MMI)
Is the test
passed after the rear cover
is installed?
Yes
The 1 kHz single-tone speaker and
the PCB resonate to produce noise,
resulting in high THD. The test is
passed after the rear cover is
installed. Ask the audio R&D
engineers to handle the problem

4.11.2 Maintenance Principle

Test Point
TP3021
TP3022
2019-6-25
EML-L29V100R001 Advanced Maintenance Manual V2.1
Noise
Are the
No
speaker dust filter
and vibration diaphragm
complete and
clean?
The components
are improperly
installed in the
production line.
Ask the PQE to
take corrective
measures
Yes
Rplace main FPC and
subboard
Reassemble the
components
Replace the speaker
and ask the MQE to
analyze the cause
Check whether L2501 and L2502
malfunction or have open solder or
dry joint.
Network
SPKOUT_ P
SPKOUT_ N
Huawei Confidential
Speaker failure (manual MMI)
No sound
Yes
No
Is there no sound
occasionally?
Is the impedance
between SPKOUT_P
and SPKOUT_N
normal?
No
Is the clasp of the main FPC and
No
subboard abnormal
Is the speaker
FPC missing or installed
improperly?
No
Perform cross
verification. Is the PCBA
faulty?
Yes
Normal Standard
Same as the resistance of a normal board
Same as the resistance of a normal board
INTERNAL
Software calibration fails.
The sound is
Contact software engineers
high or low at
or restore the phone to
times
factory settings
I2C communication
failure, which can be
resolved using software
tolerance design
Yes
Replace U2501
Yes
Are the
SPKOUT_P and SPKOUT_N
circuits on the PCBA broken or
short-circuited?
Page 42 of 67
No