LG 39LN5400 / 39LN542Y (CHASSIS:LB36B) Service Manual ▷ View online
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TROUBLESHOOTING
1. Power-up boot check
Check stand - by Voltage.
P401 3, 5pin : +3.5V_ST
Check 18pin Power connector.
Main B/D 3.5V Line
Short Check
Check X201 clock
24 MHz
Replace X201.
Check P401 PWR_ON.
1pin : 3.3V
Replace Mstar(IC101) or Main board.
Check Multi Voltage
P401 9, 10pin : 24V
/ 13, 14, 15pin:12V
Replace Power Board.
Check DRV ON Control
P403 2 pin : High
Check Power Board.
Check IC402/3/7 Output Voltage
IC402 : 2.5V
IC403 : 1.15V
IC407 : 1.5V
Q403 : 3.3V
Replace IC402, IC403, IC407, Q403
Re- download software.
Check stand - by Voltage
L404, L408 : +3.5V
Replace L404, L408.
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
ok
No
No
ok
Replace Power board.
ok
No
No
No
No
No
No
No
No
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2. Digital/Analog TV Video
3. AV Video
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.
Check input signal format.
Is it supported?
Check AV Cable for damage
for damage or open conductor.
Check JK1702, CVBS Signal Line
R1722
ok
ok
ok
No
Replace Jack.
ok
Check CVBS_DET Signal.
Replace R1713.
No
Check Mstar LVDS Output.
Replace Mstar(IC101) or Main Board.
No
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4. Component Video
5. HDMI Video
Check input signal format.
Is it supported?
Check Component Cable
for damage or open conductor.
Check JK1702
Y/PB/PR signal Line.
ok
ok
ok
No
Replace Jack.
Check COMP_DET Signal.
Replace R1712 or R1713.
No
Check Mstar LVDS Output.
Replace Mstar(IC101) or Main Board.
ok
No
Check input signal format.
Is it supported?
Check HDMI Cable conductors
for damage or open conductor.
Check EDID
R832, R833, R834, R835 I2C Signal.
Check JK801, JK803.
ok
ok
ok
No
No
Replace the defective IC or re-download EDID data.
ok
Replace Jack.
Check HDMI Signal.
Check other set
If no problem, check signal line.
ok
No
Check Mstar LVDS Output.
Replace Mstar(IC101) or Main Board .
ok
No
Replace Main Board.
No
Check HDMI_DET (HPD).
No
Replace R803, R801, R826, R807, R817, Q801, R819, R818, R830.
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6. MHL Video
7. All Source Audio
Check input signal format.
Is it supported?
Check MHL Cable conductors
for damage or open conductor.
Check MHL Signal (R214, R215)
Check JK803
ok
ok
ok
No
No
Replace the defective IC or re-download EDID data
ok
Replace Jack
Check MHL Signal
Check other set
If no problem, check signal line
ok
No
Check Mstar LVDS Output
Replace Mstar(IC101) or Main Board .
ok
No
Replace Main Board
No
Check CD_Sense, Cbus, Vbus
No
Replace R810, R802, R831, R830, IC802, D800
Check the TV Speaker Menu
(Menu - > Audio - > TV Speaker)
On
ok
ok
Check Output Signal P3401
1, 2, 3, 4 pin.
Replace Audio AMP IC(IC3401).
ok
No
Check Connector & P3401
Replace connector
if found to be damaged.
ok
No
Check speaker resistance
and connector damage.
Replace speaker.
ok
No
Off
Toggle the Menu.
Check AMP IC(IC3401) Power
24V, 3.3V
No
Replace Amp IC(IC501).
Check Mstar I2S Output
IC3401 37,38,39 Pin
No
Check signal line. Or replace Mstar(IC101).
Check Mstar AUDIO_MASTER_CLK
R148
No
Replace Mstar(IC101) or Main Board.
ok
Check AMP I2C Line
R3406, R3407
No
Check signal line. Or replace Mstar(IC101).
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