For Zeniths with 9-86 & older flat & hybrid chassii (9-27).
clean, tighten & reset module.
Boards with socketed IC's ( up to F line IIRC) should have IC's
soldered in. The sockets are more trouble than the IC's.
Clean normal-align switch, APC & ACC pots.
Adjust APC in align for fewest color bars. Dont remember ACC procedure.
The IC's are super common & used in other brands.
A few stupid things are color turned down, FT off, dirty Chromatic or
Color Sentry switch ( when used ).
Barely any off board parts will cause no color. Actual fails will
be an IC 95% of time.
BTW ANY Zenith with modules & plug in semi's always suspect the sockets
especially if intermitant. Starting around F-line (1975) they were eliminated
& all Zenith rebuilts had sockets removed.
73 Zeno
LFOD !