Flash Memory Circuit - Huawei U8815 Maintenance Manual

U8815
Maintenance Manual
circuits: R204 and C232; R3101 and C3101, outputting the system main clock to the main
chip through the PM.
32.768 kHz crystal oscillator is input to PM8029 and then to the system through the PM.

Failure: The handset cannot be powered on, or easily stops working. Check the 32.768 kHz
crystal oscillator, and check whether signal is available and frequency is stable on crystal
oscillators X301 and U3101.
Solution: Replace X301 or U3101. If the problem persists, replace PM8029.
Table 9-3 describes the signals in the circuit diagram in this section.
Table 9-3 Description of the signals in the circuit diagram in this section
Signal
XTAL32K
_OUT
XTAL32K_IN
VREG_TCXO
TRK_LO_ADJ
RTR6285_TCXO Output from the 19.2MHz
TCXO

9.2.4 Flash Memory Circuit


The following figures show the flash memory circuit diagrams.
Issue 1.0 (2012-02-13)
Troubleshooting Process
Description
Input to the 32.768kHz main
clock
Output from the 32.768kHz
main clock
19.2MHz crystal power supply
The control signal of 19.2MHz
output frequency
clock
Output from the 19.2MHz
clock
Circuit block diagram
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9 Principles and Failure Analysis
Reference Measurement or
Wave Form
2.85 V
None
32