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Only for training and service purposes
4. TROUBLE SHOOTING
4.10 Power ON Troubleshooting
4. Troubleshooting (BB)
Start
Power On sequence of GD880 is :
Power key press
Æ
PM_ON_SW(D302) go to low
Æ
PM7540 Power Up
Æ
VMSMC1_1.35V(C408),
VMSMC2_1.25V(C420), VMSME_1.8V(C416), VMSMP_2.6V(C410), VMSMA_2.6V(C405), VTCXO_2.85V(C214)
power ON
Æ
Phone booting and PS_HOLD(D400) go to High
Battery voltage. higher
than 3.70V(OCV)?
TP1 or TP6 high to low
Change or charging the
Battery
1. Check correctly connecting
Sub PCB(CN200) connector and
NO
YES
NO
TP1 or TP6 high to low
when key press?
TP2, TP3, TP4, TP7, TP8, TP10
power up?
Sub_PCB(CN200) connector and
main B/d connector(CN500)
2. Check correctly working power key
Change the Main board
YES
NO
Is clock ok?
TP9 : 19.2M
TP5 : 32.768Khz
Change the Main board
YES
YES
NO
NO
YES
LCD is turn on?
1. Check correctly connecting
Sub B/d CN100 and LCD module
NO
YES
Change LCD module
Redownload sw image
*OCV( open circuit voltage)