47SL90QD-CA (CHASSIS:LC91L) - LG TV Service Manual (repair manual). Page 14

Read LG 47SL90QD-CA (CHASSIS:LC91L) Service Manual online

- 14 -
1. TV/CATV doesn’t display
TROUBLESHOOTING
2. DTV doesn’t display
Check the  TP output data of TU1804
Can you see the normal signal?
NO
Could you measure voltage of TU1804 &
IIC lines?
Are they all normal?
NO
You should check power line
& IIC lines.
YES
You should replace Main Board.
YES
Check the output  of Main IC(IC100).
Especially you should check
The H,V sync and clock.
Can you see the normal waveform?
YES
NO
After checking the Power of Main IC(IC100) you
should decide to replace Main IC or not.
This board has big problem because Main
IC(IC100) have some troubles.
After checking thoroughly all path once again,
You should decide to replace Main Board or not.
Could you measure voltage of IC1804 & IIC
lines?
Are they all normal?
NO
You should check power line
& IIC lines.
YES
Check TU1100.
Can you see the normal signal?
Check the output  of TR(Q1102).
Can you see the normal waveform?
Check the output  of Main IC(IC100).
Especially you should check
The H,V sync and clock.
Can you see the normal waveform?
YES
YES
NO
Could you measure voltage of TU1100 &
IIC lines?
Are they all normal?
YES
NO
You should check power line
& IIC lines.
YES
You should replace Main Board.
NO
You should decide to replace TR (Q1102) or not.
NO
After checking the Power of Main IC(IC100) you
should decide to replace Main IC or not.
This board has big problem because Main
IC(IC100) have some troubles.
After checking thoroughly all path once again,
You should decide to replace Main Board or not.
Page of 35
Display

Click on the first or last page to see other 47SL90QD-CA (CHASSIS:LC91L) service manuals if exist.