Daewoo SD-8100, Service Manual

Page: 19 / 63

19
TROUBLESHOOTING
No sound in AV-F E-E
mode
Is there Audio at IC253
pin#2,12 in AV-F mode?
Is AV-F Audio signal output
at IC253 pin#14,15?
Is there AV-F Audio at IC252
pin#5,14?
Is 12V obtained at IC253
pin#16?
YES
IC601 pin#27
A.Mute is L
or H?
Check POWER circuit.
A.d. AV-F E-E
YES
NO
NO
NO
Check signal flow circuit
IC251 , IC252.
Is 12V obtained at IC252
pin#16?
Is AV-F Audio signal output at
IC252 pin#3,13?
Check POWER circuit.
NO
YES
NO
IC601 pin#31 is L?
pin21 is H?
Is about 3.5V obtained at
IC252 pin#9?
Is about 8V obtained at
IC252 pin#10?
YES
Replace IC252.
Check IC601.
Check
R923,R924,R925,R926
NO
NO
C at Q904 is L or H?
YES
Check
IC601.
Check Output JACK.
Check Q904,Q905,
R937, R938, R939
H
H
L
L
YES
YES
IC601 pin#32 is L?
Check IC601.
NO
Is 3.5V obtained at IC253
pin#10,11?
Check R298, R299,R646, R647
NO
Check Input JACK.
(FRONT AV)
Replace IC253