Read LG 42SL90-UA (CHASSIS:LA92S) Service Manual online
Check JK100 on main PCB, JK101 on sub PCB(side AV PCB)
Can you see the normal waveform?
Can you see the normal waveform?
NO
JK100(main PCB),JK101(Side AV PCB) may have problem. Replace this Jack.
Check the input (Pin U2,T1) of LGE3369(IC301).
Measure waveform at C614, C620 because it’s more easy to check.
Can you see the normal waveform?
Measure waveform at C614, C620 because it’s more easy to check.
Can you see the normal waveform?
LA92S Trouble shooting guide – AV
YES
Video
NO
This board has big problem because Main chip(LGE3369) have some troubles.
After checking thoroughly all path once again, You should decide to replace LGE3369 or n
After checking thoroughly all path once again, You should decide to replace LGE3369 or n
Check all power domain of LGE7329 (IC801)
(3.3V, 1.9V_CORE,1.26V)
(3.3V, 1.9V_CORE,1.26V)
& crystal output (X800 / 12MHz)&FRC_RESET
Measure Power & waveform at L800,L801,L802,L803,
L804,L806
because it’s more easy to check.
Can you see the normal waveform?
L804,L806
because it’s more easy to check.
Can you see the normal waveform?
YES
This board has big problem because FRC chip(LGE7329) have some troubles.
After checking thoroughly all path once again, You should decide to replace
LGE7329.
Although you replace it, you cannot see normal display, decide to replace
After checking thoroughly all path once again, You should decide to replace
LGE7329.
Although you replace it, you cannot see normal display, decide to replace
Main chip(LGE3369)
YES
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