S7-PRO Maintenance Manual (Basic Version V2.1)
INTERNAL
2012-07-20
Huawei Proprietary and Confidential
Copyright © Huawei Technologies Co., Ltd.
Page 51 of 97
Power-on fails due to low current
Check the U48 output and
measure whether the voltage
difference between C665 and
C624 is 4.2 V
Check the U7 output and measure
whether the voltage difference
between C418 and C419 is 1.8 V
Perform eMMC programming
again (U12)
No
Yes
Yes
Replace U48
Replace U7
No
9.3 Charge Failure
The Mediapad charging management circuits are shown in the following figure.
Principle: The DC regulated power supply provides the 5 V/3 A power supply to the DC-DC
circuits in the MAX8903, and MAX8903 and the power is output through VBAT and
VPH_PWR respectively.
Analysis: The U48 manages the charging of S7 Pro. For the maintenance procedures upon
charge failure, see the Appendix 1 (diagram of PRO components).
