LG 21FS4RLX Service Manual page 16

4) No Picture/ No Sound
OK
Check IC11 pin 83,
84, 85 (R, G, B out)
NO
Check the waveform
pin73(H-out)
OK
P904A (R, G, B out
of IC501)
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Only for training and service purposes.
NO
NO
Check IC11 pin 83,
84, 85 (R, G, B out)
Check pin3 Reset
Voltage
Check pin8, 12 SCL,
SDA
Replace IC11
Is any OSD displayed?
Check receiving system in MENU
& execute Auto - Program
Does the auto - Program
operate properly
Store on manual -program MENU
NO
Check SMPS Trans
Secondary Voltage
OK
OK
NO
Check IC12(EEPROM)
& SCL, SDA, Line
OK
P904A (R, G, B out
of IC11)
- 16 -
OK
OK
OK
Go to No sound/
picture OK
LGE Internal Use Only