Tuner/If Circuit - Zenith D35 Service Manual

9. Tuner/IF CIRCUIT

(1) No Picture on the TV screen
No picture on the TV
screen
YES
Does the Video signal at
the TU701 Pin24.
YES
Does Sync appear at
IC501 Pin54.
YES
Does the Video signal at
the IC501 Pin45.
YES
Does the Video signal at
the IC802 Pin30.
YES
Check the signal flow from IC802
Pin30 to JK801 Vide oout.
NO
Is +33V applied to TU701
Pin16?
Is +5V applied to TU701
Pin13?
Does the Clock signal
appear at TU701 Pin11?
Does the data signal
appear at TU701 Pin12?
Replace Tuner.
NO
Check the signal flow from
TU701 Pin24 to IC301 Pin31.
NO
Check the signal from IC301
Pin52 to IC501 Pin43.
NO
Check the signal from IC501
Pin45 to IC802 Pin1.
3-20
NO
YES
NO
YES
NO
YES
NO
YES
Check 33V line.
Check 5V line.
Check the lIC Clock Signal
of µ-COM Pin90.
Check the lIC Data Signal
of µ-COM Pin60.