Y/C Circuit - LG GC260W Service Manual

4. Y/C CIRCUIT

(1) No Video in EE Mode,
No Video in EE Mode
Does the Video signal
appear at the IC301 Pin 48?
YES
Is 5V applied to the IC301
Pins 18, 24, 42, 55, 72, 91?
YES
Does the Video signal
appear at the IC301 Pin 65?
YES
Does the Video signal
appear at the IC501 Pin 50?
YES
Does the Video signal
appear at the Emitter termi-
nal of the Q701?
Check the Video Input
NO
Jack.
(Line In Jack)
NO
Check the 5.2V, 5.4VA
Line. (Power Circuit)
NO
Is I 2 C BUS signal applied to
the IC301 Pins 68, 69?
Chck the path of the signal
NO
between the IC301 Pin 5
and IC501 Pin 50.
Does the 12V appear at
NO
the Emitter terminal of the
Q701.
Replace the Q701.
3-13
NO
YES
NO
YES
Check the System Circuit.
(Refer to 'SYSTEM I 2 C BUS
CHECK Trouble Shooting')
Check C316. (AGC)
YES
Replace the IC301.
Check the 12V Line.
(Power Circuit)