Huawei P20 - Block Nuisance Calls

EML-L29V100R001 Advanced Maintenance Manual V2.1
INTERNAL
2019-6-25
Huawei Confidential
Page 47 of 67
4.14 Wi-Fi and Bluetooth Failure
4.14.1 Maintenance Process
Wi-Fi failure (found in MT)
during phone assembly
Perform cross
verification. Is the PCBA
faulty?
No
Yes
Is the coaxial
cable damaged or
missing?
No
Yes
Re-fasten, replace, or
re-assemble the
coaxial cable
The phone is
incorrectly assembled
in the production line.
Ask the PQE to take
corrective measures
Replace the
front cover
Use the
tweezers to
install the edge
connector of
the antenna
Yes
No
Yes
Is the
Wi-Fi antenna
missing?
Is the edge
connector of the Wi-Fi
antenna raised or not in
position?
No
Are there
obvious traces
of pressing on the edge
connector of the
Wi-Fi
antenna?
No
The antenna pins are
too low. Use the
tweezers to adjust the
antenna pins
Replace the front
cover
Yes
Is the
resistance between
the edge connector and the
spring attached over
2 ohms?
Yes
No
Replace the
front cover
Wi-Fi failure (found
in BC) during PCBA
testing
Is the
failure rectified after
the WL_EN is
enabled?
Yes
No
No
Yes
Is the
Wi-Fi chip clock
normal?
Is the power
supply normal?
Yes
Is the power
of nodes in the Wi-Fi
circuit normal?
Yes
If there are no
soldering issues,
replace U300
If there are no
soldering issues,
replace U5100
If there are no
soldering issues,
replace U5100
No
No
Check the circuit for
faulty components
4.14.2 Maintenance Principle
Test Point
Network
Normal Standard
LB5201
VOUT_HLDO
1.2 V
LB5204
VOUT_LNLDO_1
1.8 V
C5215
VOUT_PA3P3
3.3 V