Power On Troubleshooting - LG E900 Service Manual

4.10 Power ON Troubleshooting

Power On sequence of LG-E900 is :
Power key press KPD_PWR_N(VA804) go to low
MSMC1_MODEM_1.23V(C416), MSMC2_APC_1.23V(C417), VREG_MSME_1.8V(C433),
VREG_MSMP_2.6V(C430), VREG_MSMA_2.6V(C429), VREG_TCXO_2.85V(C427)
power ON Phone booting and PS_HOLD(D404) go to High
Start
Battery voltage. higher
than 3.5V?
YES
TP1 high to low
when key press?
YES
TP2, TP3, TP4,
TP5, TP6, TP7 power up?
TP10 is high ?
YES
Is clock ok?
R427 : 19.2M
C462 : 32.768Khz
YES
Redownload sw image
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Only for training and service purposes
PM7540 Power Up
NO
Change or charging the
Battery
NO
1. Check correctly working
power key
NO
Change the Main
board
NO
Change the Main
board
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4. TROUBLE SHOOTING
4. Troubleshooting
LGE Internal Use Only