G700-U10 Smartphone
Maintenance Manual
10 Circuit and Failure Analysis
Issue 1.0 (2013-07-22)
Huawei Proprietary and Confidential
Copyright © Huawei Technologies Co., Ltd.
35
Figure 10-7
Troubleshooting excessive current startup failures
Connect the phone to a fake
battery and maintenance power
supply, power on the phone,
and observe the current
Is VBAT short-
circuited to the
ground?
Excessive
current
Replace the faulty
component
Are the VCORE,
VAPROC, and VDD18
short-circuited?
Resolder or replace
U202
Replace the faulty
component
N
Y
N
Y
Startup failure
Circuit Signals
Table 10-1
Circuit signals of this section
Signal
Description
Reference Value or Waveform
VBAT
Battery voltage
3.2 V to 4.2 V
VCORE
Digital core voltage
1.1 V
VAPROC
Processor voltage
1.2 V
VDD18
I/O voltage
1.8 V