LG 42SL90-UA (CHASSIS:LA92S) Service Manual ▷ View online
LA92S Trouble shooting guide – TV/CATV
Check TU500 Pin16(SIF)
Can you see the normal signal?
Can you see the normal signal?
Check the input (Pin W2) of LGE3369((IC601).
Measure waveform at C643 because it’s more easy to check.
Can you see the normal waveform?
Measure waveform at C643 because it’s more easy to check.
Can you see the normal waveform?
YES
NO
Could you measure voltage of TU500 & IIC lines?
Are they all normal?
Are they all normal?
NO
You should check power line
& IIC lines.
& IIC lines.
YES
You should replace TUNER.
NO
After checking audio signal line, you should decide to replace item or not.
Audio(In)
LA92S Trouble shooting guide – AV/Component/RGB-PC
Audio(In)
Check JK100, JK101, JK102, JK103 on main PCB and JK101
on Side AV PCB Can you see the normal waveform?
on Side AV PCB Can you see the normal waveform?
NO
JK100, JK101, JK102, JK103 on main PCB and JK101 on Side AV PCB
may have problem. Replace this Jack.
Check the input (PinAA3,Y1,AE1,AF3,AE3,AE2,AA1
AB1,AB2,AC2,AB3,AC3) of LGE3369(IC601).
Can you see the normal waveform?
AB1,AB2,AC2,AB3,AC3) of LGE3369(IC601).
Can you see the normal waveform?
NO
YES
After checking audio signal line, you should decide to replace item or not.
YES
Check the Output (Pin Audio_MASTER_CLK ,MS_LRCK
MS_SCK,MS_LRCH) of LGE3369(IC601).
Can you see the normal waveform?
MS_SCK,MS_LRCH) of LGE3369(IC601).
Can you see the normal waveform?
NO
After checking audio signal line, you should decide to replace item or not.
Check IC301(NTP-3100L) L304/L305
YES
NO
After checking audio signal line, you should decide to replace item or not.
LA92S Trouble shooting guide – HDMI
Audio(In)
Check input connect JK200,JK201,JK202,JK203
Can you see the normal waveform?
Can you see the normal waveform?
JK200,JK201,JK202,JK203 may have problem. Replace this Jack.
After checking the Power of this chip, you should decide to replace this or not.
After checking the Power of this chip, you should decide to replace this or not.
YES
YES
YES
NO
NO
NO
NO
After checking the Power & Select Pin & Etc of this chip, you should decide to replace this or not.
Check DDC communication lines
(IC200)
(IC200)
Check the output of TDA9996HL(IC200)
_HDMI1,2,3
_HDMI1,2,3
or HDMI4.
.
Can you see the normal waveform?
Check HDCP communication lines(IC105)
YES
Check the Output (Pin Audio_MASTER_CLK ,MS_LRCK
MS_SCK,MS_LRCH) of LGE3369(IC601).
Can you see the normal waveform?
MS_SCK,MS_LRCH) of LGE3369(IC601).
Can you see the normal waveform?
Check IC301(NTP-3100L) L304/L305
YES
NO
After checking the Power & Select Pin & Etc of this chip, you should decide to replace this or not.
NO
After checking the Power & Select Pin & Etc of this chip, you should decide to replace this or not.
LA92S Trouble shooting guide – Speaker
Audio(Out)
Check the output (Pin A8,B7,C7,D8) of LGE3369(IC601).
Measure waveform at R160,R161,R162,R163 because it’s more easy to check.
Can you see the normal signal?
Measure waveform at R160,R161,R162,R163 because it’s more easy to check.
Can you see the normal signal?
Check the input (Pin 7,17,18,19) of NTP3100((IC301).
Can you see the normal waveform?
Can you see the normal waveform?
YES
NO
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 BCM3553 o
After checking thoroughly all path once again, You should decide to replace BCM3553 o
After checking audio signal line, you should decide to replace item or not.
YES
NO
After checking the Power & I2C & Reset of this chip, you should decide to replace this o
NO
YES
After checking audio signal line, you should decide to replace item or not.
Check the connector & Speaker
Check the Output (Pin Audio_MASTER_CLK ,MS_LRCK
MS_SCK,MS_LRCH) of LGE3369(IC601).
Can you see the normal waveform?
MS_SCK,MS_LRCH) of LGE3369(IC601).
Can you see the normal waveform?
Check IC301(NTP-3100L) L304/L305
YES
Click on the first or last page to see other 42SL90-UA (CHASSIS:LA92S) service manuals if exist.