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Copyright © 2008 LG Electronics. Inc. All right reserved.
Only for training and service purposes
LGE Internal Use Only
4. TROUBLE SHOOTING
4.9 Power ON Troubleshooting
Power On sequence is :
PWR key press
Æ
PM_ON_SW_N(PM6650 KPDPWR_N pin(24)) go to low(R520)
Æ
PM6650 Power Up
Æ
VREG_MSMC_1.25V(C545), VREG_MSME_1.8V(C546),
VREG_MSMP_2.7V(C535), VREG_MSMA_2.6V(C533), VREG_TCXO_2.85V(C527)
power up and system reset assert to MSM
Æ
Phone booting and PS_HOLD(D502)
assert to PMIC
Battery voltage. higher
than 3.20V?
R520 go to low
when key press?
NO
YES
YES
YES
YES
NO
NO
NO
Æ
Æ
Æ
Æ
Start
Change the main board
VREG_MSMC_1.25V
VREG_MSME_1.8V
VREG_MSMP_2.7V
VREG_MSMA_2.6V
VREG_TCXO_2.85V
power up?
Is clock ok?
C150 : 19.2M
X500 : 32.768KHz
Change or charging the Battery
Check the Key Dome
Change the main board
Check the TCXO