LG 55LM4610 / 55LM4650 (CHASSIS:LB21B) Service Manual ▷ View online
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TROUBLE SHOOTING
1. Power-up boot check
Check stand-by Voltage.
P401 or P404 9~12pin : +3.5V_ST
Check Power connector
Main B/D 3.5V Line
Short Check
Check X201 clock
24 MHz
Replace X201
Check P401 or P404 PWR_ON.
1pin : 3.3V
Replace Mstar(IC101) or Main board
Check Multi Voltage
P401 or P404 2~4pin:24V
17, 19, 21 pin:12V
Replace Power Board
Check Inverter Control & Error Out
P401 or P404 18 pin : High
P401 or P404 24 pin : low
Check Power Board or Module
Check IC402/3/7 Output Voltage
IC402 : 2.5V
IC403 : 1.1V
IC407 : 1.5V
Q403 : 3.3V
Replace IC402/3/7, Q403
Re-download software.
Check LVDS Power Voltage
Q409 : 12V
Replace Q409
Check Mstar LVDS Output
Replace Mstar(IC101) or Main Board
Change Module
ok
ok
ok
ok
ok
ok
ok
ok
No
No
No
No
No
No
No
No
No
ok
Replace Power board.
ok
- 17 -
Check RF Cable & Signal
Check Tuner 3.3V Power
L3703
Replace L3703
Check Tuner 1.8V Power
IC3703 2 pin : 1.8V
Check IF_P/N Signal
TU3700 10/11 Pin
Replace IC3703
Check Mstar LVDS Output
Replace Mstar(IC101) or Main Board
.
ok
ok
ok
ok
No
No
No
No
Bad Tuner. Replace Tuner
.
2. Digital TV Video
3. Analog TV Video
Check RF Cable & Signal
Check Tuner 3.3V Power
L3703
Replace L3703
Check Tuner 1.8V Power
IC3703 2 pin : 1.8V
Replace IC3703 .
Check Mstar LVDS Output
Replace Mstar(IC101) or Main Board
.
ok
ok
ok
No
No
No
Check CVBS Signal
TU3700 8 Pin
ok
No
Bad Tuner. Replace Tuner
.
- 18 -
Check input signal format.
Is it supported?
Check AV Cable for damage
for damage or open conductor
Check JK1601
CVBS Signal Line
R246
ok
ok
ok
No
Replace Jack JK1601
ok
Check CVBS_DET Signal
Replace L1603
No
Check Mstar LVDS Output
Replace Mstar(IC101) or Main Board
.
No
4. AV Video
5. Component Video
Check input signal format.
Is it supported?
Check Component Cable
for damage or open conductor.
Check JK1601
Y/PB/PR signal Line
ok
ok
ok
No
Replace Jack JK1601
Check COMP_DET Signal
Replace L1601, R1614
No
Check Mstar LVDS Output
Replace Mstar(IC101) or Main Board
.
ok
No
- 19 -
Check input signal format.
Is it supported?
Check RGB Cable conductors
for damage or open conductor
Check EDID
I2C Signal
JK1104 Pin12, 15 (SDA,SCL)
Check JK1104
H/V_Sync/R/G/B Signal Line
ok
ok
ok
No
No
re-download EDID data ,Replace Mstar(IC101) or Main Board
ok
Replace Jack
Check DSUB_DET
Replace R1146 or R1147
No
Check Mstar LVDS Output
Replace Mstar(IC101) or Main Board
.
ok
No
6. RGB Video
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