MediaPad 7 Lite Maintenance Manual
INTERNAL
2012-10-08
Huawei Confidential
Page 40 of 82
9.2.2 Startup Failure Due to Low Current
The following figure shows the principles of the power supply system.
Adjust the voltage of the DC regulated power supply to 5 V/3 A. Use the DC regulated power
supply to power the LITE_USB interface. The current is about 120 mA after MediaPad 7 Lite
is powered on. This usually occurs when the coulometer or output voltage is abnormal.
Startup failure due to
low current
Startup failure due to
low current
Check the output voltage
of the U1801 and check whether the voltage of the
C1822/C1823 is 3.7 V.
No
Replace the
U1801.
Yes
Check whether
the output voltage of the U9000/U9001/U9002/U9003
is normal.
No
Check the
circuits related
to the U9000/
U9001/U9002/
U9003.
Yes
Replace the U1800.
The following figure shows the principles of the coulometer.
