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LGE Internal Use Only
Copyright © 2008 LG Electronics. Inc. All right reserved.
Only for training and service purposes
6. Trouble shooting
- 107 -
6.12.2 Power circuit
√
Output voltage (=LDO output of U102)
- check LDO output voltage of U102
→
I.e. VRF1_2V85 (C125),
VRF2_1V5 (C118),
VRF3_2V85 (C121)
Power Circuit
Check Voltage of TP1,
TP2 & TP3.
Is it correct?
Power is OK.
See next part.
Replace PCB
NO
YES
0.1u
C113
VRF3_2V85
VBAT
0.1u
C120
VVIB_2V8
C108
2.2u
220n
C106
VRF3_2V85
C104
220n
100p
C112
2.2u
C121
C114
0.01u
1u
C105
VAUX_2V9
TP102
VRTC_2V0
47nH
L101
VBAT
L102
47nH
VRF2_1V5
VRF3_2V85
VRF3_2V85
220n
VUSB_3V1
C128
C110
VRF3_2V85
1u
C103
1u
VBAT
R111
390K
C109
2.2u
R112
4.7K
0.01u
C116
VBAT
C102
1u
C126
VSD1_1V5
VRF3_2V85
220n
C117
0.01u
VSS_LDO2
D6
VSS_LDO3
C3
L12
VSS_MAIN_1
VSS_MAIN_2
L10
VSS_MAIN_3
M10
J8
VSS_MAIN_4
L8
VSS_MAIN_5
VSS_MS
F3
E18
VSS_RTC
VUSB
B7
VVIB
D12
V4
VSSRF11
V5
VSSRF12
VSSRF13
V6
VSSRF14
W1
N2
VSSRF2
N3
VSSRF3
P2
VSSRF4
R2
VSSRF5
T2
VSSRF6
VSSRF7
U2
VSSRF8
U3
VSSRF9
U6
VSS_AUDIO
E3
H2
VSS_EP
E11
VSS_LDO1
C7
VIO
C10
VLED
A7
VMMC
A3
VPLL
VRF1
A2
B4
VRF2
B1
VRF3
A8
VSIM
M2
VSSRF1
V2
VSSRF10
VDDPLL
W6
VDDP_EBU_1
V19
L1
VDDRX
T3
VDDTRX
VDDTX
W4
W5
VDDVCO
VDDXO
V7
VDD_FUSE_FS
M4
L11
VDD_MAIN_1
VDD_MAIN_2
M11
VDD_MAIN_3
L9
M9
VDD_MAIN_4
D7
VDD_REF
VDD_RF2PLL
B3
D18
VDD_RTC
E1
VAUDIO
D11
VAUX
VBAT_AUDIO
E2
VBAT_BSW_USB_MMC
C6
VBAT_LDO1
E12
VBAT_LDO2
B8
B2
VBAT_RF13
A5
VDDCHARGE
VDDDIG
T6
P4
VDDMS
W3
SENSE_IN1
D5
SENSE_IN2
C4
A1
NC1
A19
NC2
NC3
W19
M0
H3
J3
M1
M10
F4
M2
G4
H4
M7
M8
G3
J4
M9
CHARGE_UC_SCAN_IN1
C8
C5
CH_GATE
A4
CH_SOURCE
K1
AGND_MS1
AGND_MS2
K4
C122
KDR331V
3
1
2
120p
D101
C124
1u
R104
0
1u
1u
C107
C127
0.01u
C123
C118
1u
C131
0.1u
0.1u
C130
0.1u
C129
VSIM_2V8
12p
C111
0
R105
VRF1_2V85
VIO_2V62
0
R591
R113
100K
VAUDIO_2V5
VRF2_1V5
VRF1_2V85
0.01u
C115
1u
C125
VMMC
C119
2.2u
VRF3_2V85
2.2u
C101
VPLL_1V5
VSD2_1V8
REMOTE_ADC
OVP_VUSB
OVP_VCHG
BAT_ID
RF_TEMP
Fig 2 Debugging flowchart of Power circuit
Fig 3 Power circuit (U104)
TP1
TP2
TP3
TP2
TP1
TP3
Summary of Contents for KC550
Page 1: ...Date May 2008 Issue 1 0 Service Manual Model KC550 Service Manual KC550 Internal Use Only ...
Page 182: ...Note ...
Page 183: ...Note ...