Power On Troubleshooting - LG D410 Service Manual

3.16 Power ON Troubleshooting

The main power source of LGD410 is provided by 1 chip which isPM8226. Since MSM8226 only powers up
normally when MSM8226 is properly powered therefore, PM8226is the actual one to take look at.
Power ON sequence of LGD410 is,PWR key press -> BAT_FET_N goes low-> GPIO8 High -> VREG_S3 High -> VREG_L6
High -> VREG_L12 High -> XBB_CLK -> PON_RESET_N goes high -> PS_HOLD High.
VREG_L12_1V8
BB_CLK has special layout and component requirements.
Please refer to 80-NC833-14 for more information.
VREF_BAT_THERM
VREF_LPDDR2
LGE Internal Use Only
PM_KYPD_PWR_N
PMIC_SPMI_CLK
PMIC_SPMI_DATA
TP2
X4100
1RAA19200AAA
4 3
SENSOR XTAL2
1 2
XTAL1 GND1
19.2MHz
(07/01)
Rev1,0) ESD
TP5
JTAG_PS_HOLD
R4104
MSM_PS_HOLD
R4105
TP4103
MSM_RESIN_N
R4107
R4108
TP4
QCT Ref.J (11/5)
BB_CLK_EN
WTR0_XO_IN
XO_G_TCXO
R4110
BB_CLK
R4112
NFC_CLK_OUT
R4114
SLEEP_CLK
QCT Ref.checklist
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3. TROUBLE SHOOTING
TP4100
85
CBL_PWR_N
102
KPD_PWR_N
108
OPT_2
119
OPT_1
100
10K
PS_HOLD
101
TP1
0
RESIN_IN
77
RevB
PON_RESET_N
112
0
SPMI_CLK
123
0
SPMI_DATA
120
XO_THERM
63
GND_XOADC
5
XTAL_19M_IN
6
XTAL_19M_OUT
62
GND_XO_BUFF
17
GND_XO
44
BB_CLK1_EN
TP3
13
RF_CLK1
39
RF_CLK2
31
0
BB_CLK1
42
0
BB_CLK2
88
0
SLEEP_CLK1
(05/30)
169
VREF_BAT_THM
61
VREF_LPDDR
129
REF_BYP
117
GND_REF
Only for training and service purposes
U4100
PM8226