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4 . TROUBLE SHOOTING
Checking Flow
Check Battery Voltage
Push power-on key
And check the level change
of PWRKEY
Check the voltage of
The LDO outputs at U101
Logic level at KEYON of U101
Does it work properly?
THE PHONE WILL
POWER ON.
START
> 3.35V ?
YES
YES
YES
= HIGH
YES
The power-on procedure is
Completed. The problem may
YES
NO
Charge or Change Battery
NO
Check the contact of power key
Or dome-switch
NO
Replace U101
VCORE=1.8V
WCXO=2.75V
VMEM=2.8V
VRTC=1.8V
VEXT=2.8V
VSIM=2.5V (when sim card is inserted)
VABB=2.75V
VMIC=2.5V
NO
Re-download software
NO
Does it work properly?
be elsewhere.
Replace the main board
- 62 -
NO
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