DOWNLOAD LG 42CL40-UA (CHASSIS:LA92B) Service Manual ↓ Size: 5.14 MB | Pages: 45 in PDF or view online for FREE

Model
42CL40-UA (CHASSIS:LA92B)
Pages
45
Size
5.14 MB
Type
PDF
Document
Service Manual
Brand
Device
TV / LCD
File
42cl40-ua-chassis-la92b.pdf
Date
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LG 42CL40-UA (CHASSIS:LA92B) Service Manual ▷ View online

- 21 -
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?
YES
NO
NO
YES
YES
Check all power domain of LGE7329 (IC801)
(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?
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)
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
- 22 -
4. RGB PC
Check JK1201
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?
NO
YES
YES
Check all power domain of LGE7329 (IC801)
(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?
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)
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
- 23 -
5. HDMI
Check input connect 
JK500,JK501,JK502,JK503
Can you see the normal waveform?
Check DDC communication lines
(IC502)
JK500,JK501,JK502,JK503
may have problem. Replace this Jack.
Check the output of TDA9996HL(IC502)
_HDMI1,2,3 
or HDMI4. 
. 
Can you see the normal waveform?
After checking the Power of this chip, you should decide to replace this or not.
Check HDCP communication lines(IC105)
After checking the Power of this chip, you should decide to replace this or not.
YES
YES
YES
NO
NO
NO
NO
YES
YES
Check all power domain of LGE7329 (IC801)
(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?
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)
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
- 24 -
• AUDIO PATH
AUDIO TROUBLESHOOTING
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