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LGE Internal Use Only
Copyright © 2007 LG Electronics. Inc. All right reserved.
Only for training and service purposes
4. TROUBLE SHOOTING
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4.6. Power ON Troubleshooting
Power On sequence of L705i is :
PWR key press
→
KEY_ON_SW_N go to low,PM6650 KPDPWR_N pin(24)
→
PM6650 Power Up
→
VREG_MSMC_1.375V(C429), VREG_MSME_1.8V(C430), VREG_MSMP_2.7V(C423),
VREG_MSMA_2.6V(C420), VREG_TCXO_2.85V(C400) power up and system reset assert to MSM
→
Phone booting and PS_HOLD(D400) assert to PMIC
Start
Battery voltage. higher
than 3.3V?
VA601 high to low
when key press?
VREG_MSMC_1.375V,VREG_MSME_1.8V,
VREG_MSMP_2.7V, VREG_TCXO_2.85V,
VREG_MSMA_2.6V power up?
Is clock ok?
R408 : 19.2M
X400: 32.768Khz
Change the Main board
Change or charging the
Battery
Check the Key Dome
Or Check Main to Sub Con.
Change the Main board
Check the TXCO & Crystal
NO
YES
YES
YES
YES
NO
NO
NO
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