Figure 9-28 Troubleshooting Process For Transmission Failure - Huawei U8815 Maintenance Manual

U8815
Maintenance Manual

Figure 9-28 Troubleshooting process for transmission failure

In W900, just replace the U3302 detection with U3401 detection.
In GSM900 or GSM1800, just replace the U3302 detection with U3401 detection.
Table 9-7 describes the signals in the circuit diagram in this section.
Table 9-7 Description of the signals in the circuit diagram in this section
Signal
VREG_L19_2P85
VREG_RFRX1
VREG_RFTX
VREG_S3
Issue 1.0 (2012-02-13)
Failure of the W2100
transmission channel
Check U3201 when the
handset is not connected
to the RF cable.
Are pins 1 and 2 of U3201 connected?
Y
Check
whether the control
signal of the U3202 switch is
normal (For the truth table for control
signals, see
table 1.)
Y
Is the W2100PA
output of U3302 normal?
Y
Check
whether the IQ signal of U3901
and the power supply voltage
are normal.
Y
Check U401.
End
Description
Supplies power for GPS
Supplies power for RTR6285A
Supplies power for RTR6285A
Supplies power for RTR6285A
Huawei Proprietary and Confidential
Copyright © Huawei Technologies Co., Ltd.
9 Principles and Failure Analysis
N
Check U3201.
N
Check U3202 and U401.
N
Check U3402.
N
Check U3901.
Reference Measurement
or Wave Form
2.85 V
2.1 V
2.7 V
1.8 V
43