Pretty sure this is NOT the chassis with the micro problems.
Control functions are done one of 2 ways.
1) each control ( color, tint, brite etc) goes from the micro to the
jungle IC on separate lines. They will show a changing DC voltage
as you change the setting. The easy & better way IMHO.
2) data & clock lines come into the jungle IC. Its decoded within the
jungle IC. All you can do it watch for activity ( on scope) on the data line when adjusting controls. Bursts of activity may happen even when not changing controls. This is the "modern" way of doing things. Like energy star
better to avoid it at all costs !!
In any case I would say its a video problem for sure. OSD shows
a strong looking CRT & eliminates easy problems. Time to dig in.
enuf fer now
73 Zeno
LFOD !
BTW I probably have the training manual for this set if you go further.....