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4. TROUBLESHOOTING
Checking Flow
And check the level change
Logic level at KEYON of U101
START
Check Battery Voltage
> 3.35V ?
YES
Push power-on key
of PWRKEY
YES
Check the voltage of
The LDO outputs at U101
VCORE=1.8V
VMEM=2.8V
YES
VEXT=2.8V
VABB=2.75V
= HIGH
YES
Does it work properly?
The power-on procedure is
Completed. The problem may
YES
THE PHONE WILL
POWER ON.
NO
Charge or Change Battery
NO
Check the contact of power key
Or dome-switch
NO
Replace U101
VVCXO=2.75V
VRTC=1.8V
VSIM=2.85V (when sim card is inserted)
VMIC=2.5V
NO
Re-download software
NO
Does it work properly?
be elsewhere.
Replace the main board
- 66 -
NO
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