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LGE Internal Use Only
Copyright © 2008 LG Electronics. Inc. All right reserved.
Only for training and service purposes
4. TROUBLE SHOOTING
4. TROUBLE SHOOTING
< MULTIKEY PCB >
4.1 Power ON Trouble
START
No
Change main board
change
main battery
Yes
Yes
No
No
The voltage of main battery
is higher than 3.2V ?
END key operates well?
ONSWAn(D900) level is low
when END key pressed.
Follow the
keypad Trouble
shooting guide
Check the voltage.
VDD_A (C303) 2.80V
VDD_D (C304) 2.65V
VDD_E (C305) 1.8V
VDD_F (C310) 2.5V
VDD_G (C311) 2.85V
VDD_H (C309) 2.75V
VDD_K(C312) 2.75V
VDD_LP(C313) 2.2V
VBUCK(L301) 1.2V
TP01_BB
(END)
< MAIN PCB >
VDD_A
VDD_D
VDD_E
VDD_A
VDD_D
VDD_E
VDD_F
VDD_F
VDD_G
VDD_G
VDD_H
VDD_H
VCORE
TP01_BB
(END)
TP01_BB
(END)
VDD_LP
4.1 Power ON Trouble
ON_SW KEY
VA900
ICVS0514X350FR
SEND
VDDE_1V8
EVLC14S02050
VA
9
0
1
ZD3
ESD9X5.0ST5G
INSTP
AR
OK
ZD1
ESD9X5.0ST5G
INSTP
AR
D900
RB521S-30
CLR
ZD2
ESD9X5.0ST5G
INSTP
AR
END
R900
10K
10K
R901
KEYOUT1
KEYOUT2
KEYIN4
ONSWA_n
ONSWA_n
KEYIN5
KEYIN4
KEYOUT2
KEYOUT1
KEYIN5
TP01_BB
(END)
TP01_
BB(END)
1608
Local ground plane
Close to AB
BLM18PG121SN1J
Parallel with VCORE
REV.F
REV.F
2.8*2.6*1.0 0.7A 240mohm 20%
120ohm 1608 2A 50mohm Bead
Use multiple via
B1
VSS_BUCK
VBUCK
C1
L1
SIMLDO_OUT
K13
LDOA_OUT
N12
LDOC_OUT
L12
LDOD_OUT
LDOE_OUT
G14
LDOF_OUT
G13
L13
LDOG_OUT
LDOH_OUT
L14
LDOK_OUT
M14
D13
LDOLP_OUT
EXT_LDO
C12
BUCK_FB
E1
C318
10u
C310
1u
2.2u
C308
VDDD_2V65
VDDH_SMB_2V75
2.2u
C305
C324
1u
VBAT
C311
4.7u
1u
C309
VDDK_2V75
VDIGRAD_1V8
VBAT_C
R308
4.7K
VDDC_2V65
FB301
2.2u
C304
1u
C312
VCORE
4.7uH
L301
2.2u
C303
10u
C319
DNI
C317
C313
VDDE_1V8
1u
VDDG_2V85
0
R306
VDDA_2V8
0.1u
C320
VDDF_2V5
0.1u
C315
RB521S-30
D301
10u
C316
VBAT
VBACKUP
VDDE_1V8
VCORE
VDDC_2V65
VBAT
EXT_LDO
VDDA_2V8
VDDH_SMB_2V75
VDDD_2V65
VDDF_2V5
VDDG_2V85
VDDK_2V75
VDIGRAD_1V8
SIMVCC
VDD_A
VDD_D
VDD_E
VDD_H
VDD_F
VDD_K
VDD_G
VDD_LP