LG 55LD650H (CHASSIS:LA05A) Service Manual ▷ View online
No OSD Trouble Shooting guide
Check LVDS Cable
Check LCD Module
Control board
Y
Replace Cable
N
Check P400 All
Voltage Level (5V, 12V, 16V)
Check power connector and
RL_ON signal OK ?
Replace Power board
N
Y
Check Q401 output
Voltage(12V)
Y
Check Q401 application
circuit or replace Q401
N
Check TU100 Pin16(Video output)
Can you see the normal signal?
Can you see the normal signal?
Check the input(Pin1) of LPF(IC100).
Can you see the normal waveform?
Can you see the normal waveform?
YES
NO
Could you measure voltage of TU100 & IIC lines?
Are they all normal?
Are they all normal?
Check the output(pin17) of IC1500
Can you see the normal waveform?
Can you see the normal waveform?
Check the input(PinAB11) of BCM3549(IC100).
Measure waveform at C1109 because it’s more
easy to check.
Can you see the normal waveform?
Measure waveform at C1109 because it’s more
easy to check.
Can you see the normal waveform?
NO
You should check power
line
& IIC lines.
line
& IIC lines.
YES
You should replace TUNER.
NO
After checking video signal line & the Power of LPF you should decide to replace
item or not.
item or not.
NO
After checking the Power/IIC of IC1501, you should decide to replace it or
not
not
YES
This board has big problem because Main chip(BCM3549) have some troubles.
After checking thoroughly all path once again, You should decide to replace BCM3549 or not.
After checking thoroughly all path once again, You should decide to replace BCM3549 or not.
Analog RF Video Trouble shooting guide
YES
YES
Digital RF Trouble shooting guide
Check RF Cable
Check IIC Signal
TU100 #7, 8 Pin
Check IIC line and level shifter
circuit
Check LGDT3305 Output
Clock(R141), Data(R142)
, Sync(R140)
Y
Y
N
Check Tuner 5V Power
IC401
Replace IC401
Y
N
Y
Maybe LGDT3305(IC1001) has
problems
N
Check X100
and application circuit
Check IF Signal
TU1001 #10, 11 Pin
Check tuner application circuit or
replace tuner.
N
Y
Replace X1200
N
Y
Replace IC101
Check JK1704, JK1701
Can you see the normal waveform?
Can you see the normal waveform?
NO
JK1704, JK1701 may have problem. Replace this Jack.
Check the input (Pin AB11,AM19) of BCM3549(IC101).
Measure waveform at C1109 because it’s more easy to check.
Can you see the normal waveform?
Measure waveform at C1109 because it’s more easy to check.
Can you see the normal waveform?
YES
This board has big problem because Main chip(BCM3549) have some troubles.
After checking thoroughly all path once again, You should decide to replace
BCM3549 or not.
After checking thoroughly all path once again, You should decide to replace
BCM3549 or not.
AV Video Trouble shooting guide
YES
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