U8185
Maintenance Manual
9 Principles and Failure Analysis
Issue 1.0 (2012-03-23)
Huawei Proprietary and Confidential
Copyright © Huawei Technologies Co., Ltd.
33
Analysis
The memory is NUMONNYX's MCP storage chip including 4 GB (256 MB x 16) NAND
flash and 2 GB (64 MB x 32) mobile DDR SDRAM. The memory provides space for the
storage of codes, file system, and data and program running. The MCP memory and the
MSM7225A are connected with the data bus, address bus, and control signal cable.
Troubleshooting Process
Failure symptom: The phone cannot be powered on, or the power-on current is less than 100
mA.
Solution: Upgrade or load the phone's software, and check whether the Flash VREG_MSME1
voltage and peripheral components are normal. If the problem persists, replace the U601.
Table 9-2
Circuit diagram signal summary
Signal
Description
Reference
Measurement or
Wave Form
VREG_S3
Power supply
1.8 V
NAND_CS0_N
Enable pin for the flash chip; valid when at
low level
None.
NAND_RE_N
Flash read enable; valid when at low level
None.
NAND_WE_N
Flash write enable; valid when at low level
None.
NAND_CLE
Flash command latch enable
None.