Trouble Shooting - LG 21FS4RLX Service Manual

1. RF-STEREO MODEL
1) PICTURE OK / NO SOUND
Selected correct system in menu
Check the waveform IF 1 of TU101
Check the waveform at pin 4, 5 of IC11
Check the waveform at pin 4, 12 of
IC601
Check the waveform at pin 6 of IC601
Check the waveform at pin 1, 2, 14, 15
of IC601
Check the waveform at pin 3, 13 of
IC601
2) No Raster / Sound OK(1/2)
Check HV, Screen voltage of CPT
Check FBT T402
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Only for training and service purposes.

TROUBLE SHOOTING

OK
NO
OK
NO
OK
NO
OK
NO
OK
NO
OK
NO
Check R, G, B out of CPT board
Check 190V line of CPT Board &
if no problem check and Replace
Check/ Replace TU101 or Input signal
Check the voltage at pin 3, 9, 16, 43,
86, 88, 90 of UOCIII
Check the voltage at pin 57, 58 of
UOCIII
Check/ Replace Q603
Check/ Replace IC601
Check/ Replace R823, D826
Check the Heater voltage of
CPT(6~6.4 Vrms)
Check IC901,
P402A
- 14 -
NO
Check/ Replace IC11
Check the Heater pulse of FBT T402
Check RF901, P903C,
P903B, FR401
Check FBT T402
LGE Internal Use Only