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4. TROUBLE SHOOTING
Checking Flow
START
Check Battery Voltage
> 3.35V ?
YES
Push power-on key
And check the level change
of PWRKEY
YES
Check the voltage of
The LDO outputs at U101
YES
Logic level at KEYON of U101
= HIGH
YES
Does it work properly?
YES
THE PHONE WILL
POWER ON.
NO
Charge or Change Battery
NO
Check the contact of power key
Or dome-switch
NO
Replace U101
VCORE=1.8V
VVCXO=2.75V
VMEM=2.8V
VRTC=1.8V
VEXT=2.8V
VSIM=2.85V (when sim card is inserted)
VABB=2.75V
VMIC=2.5V
NO
Re-download software
NO
The power-on procedure is
Completed. The problem may
be elsewhere.
- 72 -
Does it work properly?
NO
Replace the main board
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