S7-PRO Maintenance Manual (Basic Version V2.1)
INTERNAL
2012-07-20
Huawei Proprietary and Confidential
Copyright © Huawei Technologies Co., Ltd.
Page 79 of 97
Y
Replace Z18
End
Check whether the 19.2
MHz crystal (X1) is
normal
Power on the
board
Maintenance procedures
No
No
No
No
No
No
Check whether Z22 pin 4 can
receive the GPS signal
normally
Check whether Z18 pin 4 can
receive the GPS signal
normally
Check whether the LNA U44
works normally
Check whether Z5 pin 3 and
pin 4 can receive the GPS
signal normally
Check whether QTR8615
(U23) works normally
Replace Z22
Check the input signal, output signal,
logic control signal, and power supply. If
any exception is found, replace U44
Replace Z5
Check the power supply for
U23. If any exception is found,
replace U23
Replace X1
Yes
Yes
Yes
Yes
Yes
Yes
