Aiwa HV-FX7800 Service Manual page 50

ELECTRICAL TROUBLESHOOTING -10/17
4. Y/C CIRCUIT
(1) No Video in EE Mode,
No Video in EE Mode
Does the Video signal
appear at the IC301 Pin 38?
Is 5V applied to the IC301
Pins 16, 40, 55, 58, 75, 87?
Does the Video signal
appear at the IC301 Pin 29?
Does the Video signal
appear at the IC501 Pin 17?
Does the Video signal
appear at the Emitter
terminal of the Q701?
NO
YES
NO
YES
NO
YES
NO
YES
NO
Check the Video Input
Jack.
(Line In Jack)
Check the 5V Line.
(Power Circuit)
Is I 2 C BUS signal applied to
the IC301 Pin 23, 24?
YES
Chck the path of the signal
between the IC301 Pin 29
and IC501 Pin 17.
Does the 5V appear at
the Emitter terminal of
the Q701.
YES
Replace the Q701.
-50-
Check the System Circuit.
NO
(Refer to 'SYSTEM I
CHECK Trouble Shooting')
Check C315. (AGC)
NO
Replace the IC301.
Check the 5V Line.
(Power Circuit)
2 C BUS
YES