Tuner/If Circuit - Zenith XBV613 - DVD/VCR Combination Service Manual

7. Tuner/IF CIRCUIT

(1) No Picture on the TV screen
No picture on the TV
screen
YES
Does the Video signal at
the TU701 Pin16.
YES
Does the Video signal
appear at IC501 Pin 52.
YES
Does the Video signal
appear at JK901
YES
Check the signal flow from IC501
Pin52 to JK901 Pin Video out.
NO
Is +33V applied to TU701
Pin14?
Is +5V applied to TU701
Pin3?
Does the Clock signal
appear at TU701 Pin9?
Does the data signal
appear at TU701 Pin10?
Replace Tuner.
NO
Check the signal from IC301
Pin29 to IC501 Pin50.
NO
Check the signal from IC501
Pin52 to Q924
3-17
NO
YES
NO
YES
NO
YES
NO
YES
Check 33V line.
Check 5V line.
Check the lIC Clock Signal
of µ-COM Pin71.
Check the lIC Data Signal
of µ-COM Pin72.