LG 47SL90QD-AA (CHASSIS:LB91L) Service Manual ▷ View online
Making
Revision
2009. 2 . 1
1/25
LCD TV
Symptom
Power-Up Boot Fail
P800 Pin #7~#10
Voltage Level = 5V ?
Check Power connector
OK ?
Replace Power Board
NO
YES
Revision
P800 Pin #2
Voltage level = 5V ?
YES
NO
YES
Replace MAIN B’D Q801
P800 Pin #13, 14 = 12V
P800 Pin #17, 18 = 24V ?
Replace Power Board
YES
NO
YES
MAIN B’D L815 = 3.3V ?
Replace MAIN B’D IC804
NO
YES
MAIN B’D L816 = 1.26V ?
Replace MAIN B’D IC805
NO
MAIN B’D L809 = 1.8V ?
Replace MAIN B’D IC807
YES
NO
NO
Check MAIN B’D X100 Clock
12MHz
Replace MAIN B’D IC100
YES
NO
Replace MAIN B’D IC102
NAND FLASH
YES
Replace MAIN B’D IC103
Serial Flash
NO
Replace MAIN B’D
IC300, IC301 DDR2 Memory
NO
Replace MAIN B’D IC100
NO
Making
Revision
2009. 2 . 1
LCD TV
Symptom
No OSD
2/25
Check Power connector
OK ?
Replace Power Board
P800 Pin #13, 14 = 12V
P800 Pi #17 18 24V ?
Revision
P800 Pin #20
Voltage level = 2V ↑
OK ?
Replace Power Board
YES
NO
YES
NO
Replace MAIN B’D Q802
P800 Pin #17, 18 = 24V ?
NO
YES
MAIN B’D L810 = 12V ?
Replace MAIN B’D Q805
NO
YES
Replace Main Board
YES
Check LVDS Cable
OK ?
YES
NO
Replace LVDS Cable
Making
Revision
2009. 2 . 1
LCD TV
Symptom
Digital TV Video Problem
3/25
Check RF Cable
Revision
MAIN B’D L1111 = 5V ?
YES
NO
YES
Replace MAIN B’D IC808
MAIN B’D L1112 = 3.3V ?
Replace MAIN B’D IC1103
YES
NO
YES
MAIN B’D L1113 = 1.8V ?
Replace MAIN B’D IC1105
NO
YES
MAIN B’D X1101 Clock ?
NO
Replace MAIN B’D X1101
Making
Revision
2009. 2 . 1
LCD TV
Symptom
Analog TV Video Problem
4/25
Revision
Check RF Cable
MAIN B’D L1111 = 5V ?
YES
NO
YES
Replace MAIN B’D IC808
MAIN B’D L1112 = 3.3V ?
Replace MAIN B’D IC1103
YES
NO
YES
MAIN B’D L1113 = 1.8V ?
Replace MAIN B’D IC1105
NO
YES
MAIN B’D X1101 Clock ?
NO
Replace MAIN B’D X1101
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