Power On Troubleshooting - LG D405 Service Manual

3.17 Power ON Troubleshooting

The main power source of LGD405 is provided by 1 chip which is PM8226. Since MSM8226 only powers up normally
when MSM8226 is properly powered therefore, PM8226 is the actual one to take look at.
Power ON sequence of LGD405 is,
PWR key press -> BAT_FET_N goes low -> GPIO8 High -> VREG_S3 High -> VREG_L6 High -> VREG_L12 High -> BB_CLK ->
PON_RESET_N goes high -> PS_HOLD High.
PM_KYPD_PWR_N
LGE Internal Use Only
R9607 100
TP1(R9607)
TP4(C4139)
- 107 -
3. TROUBLE SHOOTING
VREG_S1_1P15
VREG_S2_1P15
VREG_S3_1P35
VREG_S4_2P1
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Only for training and service purposes
SW9711
S1
3
4
5
6
S2