LG CF-20/21S12EH, Service Manual

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NO SOUND / PICTURE OK
Select correct
system in MENU
Check the waveform
of Q651 collector
Check the waveform
of pin3 of IC202
Check demodulated
signal of pin15
Check demodulated
of input pin of IC601 or 602
Check the Vcc
of IC601/602
Check / replace
Q651
Check the voltage
of IC101(logic)
Check / replace
Q653,654
NO PICTURE / NO SOUND
Is any OSD displayed?
Check receiving system in MENU
& excute Auto-program.
Yes
OK
Not OK
Check IC01 pin9,10
(V-Sync, H-Sync)
Check IC01 pin36,37
(XLC, EXLC)
& IC01
No
Go to
NO SOUND /
PICTURE OK
Does the Auto-program
operate properly.
Store in manual-program MENU
Check 5V, 33V & IIC Bus Line
of TUNER
Is the CVBS signal OK.
( IC501 pin6 )
Check R,G,B signal
at IC501 pin19,20,21
Check
5V, 33V &
IIC Bus Line
Yes
Not OK
Not OK
OK
Check / Replace
TUNER, IC501
Not OK
OK
Check / Replace
CPT Board component
Check
CVBS singal Line
& IC501
Check IC01 pin30,31,32
(R,G,B)
OK
Not OK