CED has an NTSC out so first try something that has it like
an old Atari 2600 or VCR. That narrows down TV or CED.
If TV its from the audio take off & detector stage. Not a lot there.
If CED I cant help. Never trained or worked on one.
& Yes they did use Hitachi & also built there own too !
Zeno
LFOD !