LG 55LH40 / 55LH41 / 55LH400С (CHASSIS:LA92B) Service Manual ▷ View online
C
2009
- 21 -
1. Side effect of OPC Function
A change of Brightness or OSD Flicker problem
Check OPC Status in the picture-Advanced
Control menu
YES
YES
This problem is side effect of OPC Function
1)A change of Brightness means Backlight dimming is operating
1)A change of Brightness means Backlight dimming is operating
by dark image because of OPC function
2)A phenomenon of flicker a specially bright area is
Side effect because of OPC
function
Recheck After OPC Off
YES
Ex1) A change of total brightness adding local bright image or caption
<In excluding
a caption
>
< In including
a caption
>
Ex2) A phenomenon of moment flicker a specially
bright area after changing channel or input mode
CATV-3
CATV-3
<Before changing channel>
<After changin g channel>
CATV-2
C
2009
- 22 -
2. AV
Check JK1202, JK1206
Can you see the normal waveform?
Can you see the normal waveform?
NO
JK1202,JK1206 may have problem. Replace this Jack.
Check the input (Pin AN17,AM19) of LGE3159(IC100).
Measure waveform at C112,C118 because it’s more easy to check.
Can you see the normal waveform?
Measure waveform at C112,C118 because it’s more easy to check.
Can you see the normal waveform?
YES
NO
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 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(LGE3159)
YES
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C
2009
3. Component
Check JK1206
Can you see the normal waveform?
JK1206
may have problem. Replace this Jack.
Check the input (Pin R1,R3,P2 and Pin V1,V2,U1)
of LGE3159(IC100).
Measure waveform at C101,C102,C103 and C115,C116,C117
because it’s more easy to check.
Can you see the normal waveform?
of LGE3159(IC100).
Measure waveform at C101,C102,C103 and C115,C116,C117
because it’s more easy to check.
Can you see the normal waveform?
YES
NO
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
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 no
- 24 -
C
2009
4. 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?
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
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 no
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