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Copyright © 2010 LG Electronics. Inc. All right reserved.
Only for training and service purposes
LGE Internal Use Only
4. TROUBLE SHOOTING
ͽͶ͑ͺΟΥΖΣΟΒΝ͑ΆΤΖ͑ΟΝΪ
`_VXZZ
4. TROUBLE SHOOTING
CHECKING FLOW
START
Is Pin3 of Q401 low
at KEY_BL_EN
= high ?
NO
Check Q401
Are all LEDs
Working?
NO
YES
Check the soldering
each R and LED
Backlight will work properly.
NO
Replace or resolder
component
YES
CIRCUIT
TP1
LD408 LD406 LD403 LD407 LD404 LD405 LD409 LD410 LD411 LD414 LD413 LD412
D401
0
51
104R
LD401
Q401
1
2
3
K001
844R
LD402
VBAT
smh
o
051
03
4
R
smh
o
051
1
3
4
R
2
34
R
s
m
ho0
5
1
3
34
R
smh
o
051
smh
o
051
4
34
R
smho051
534R
smho051
6
34
R
smho051
734R
smho051
834R
smho051
934R
s
mho051
044R
144R
smho051
244R
smho051
1.2K
R447
0.1u
C431
KEY_BL_EN
TP1