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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 U100
Logic level at KEYON signal of U100
Does it work properly?
THE PHONE WILL
POWER ON.
START
NO
> 3.35V
YES
NO
YES
NO
VCORE=1.8V
VMEM=2.8V
YES
VEXT=2.8V
VMIC=2.5V
NO
= HIGH?
YES
NO
The power-on procedure is
Completed. The problem may
be elsewhere.
YES
Figure 4-27.
Charge or Change Battery
Check the contact of power key
Or dome-switch
Replace U100
VVCXO=2.75V
VSIM=1.8V or 2.85V
VABB=2.75V
Re-download software
Does it work properly?
Replace the main board
- 90 -
NO
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