Read LG 55LH90 (CHASSIS:LA92C) Service Manual online
LH40/LH55 Trouble shooting guide – RGB PC
Check JK1201
Can you see the normal waveform?
Can you see the normal waveform?
YES
JK1201 may have problem. Replace this Jack.
NO
Check the input (Pin K1,K2,K3,L1,L3)
of LGE3159(IC100).
Measure waveform at C113,C114,C108 and R146,R149
because it’s more easy to check.
Can you see the normal waveform?
of LGE3159(IC100).
Measure waveform at C113,C114,C108 and R146,R149
because it’s more easy to check.
Can you see the normal waveform?
Video
NO
YES
YES
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?
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
Main chip(LGE3159)
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(LGE3159)
This board has big problem because Main chip(LGE3159) have some troubles.
After checking thoroughly all path once again, You should decide to replace LGE3159 or not.
After checking thoroughly all path once again, You should decide to replace LGE3159 or not.
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