Timmy
At this point I really think you need to invest in a MODERN analyst such
as the Sencore VA48 or VA62. That will give you a stable known source
that was built for your sets era. A scope is nice but an analyst
helps with other projects & do more than trace & show freq.
This is long distance servicing. VERY hard to do. A lot of us that
spent time in the biz fixin 10's of thousands of TV's could spend a
few mns looking , twisting & observing a set & know where to go.
You have stuck it out well & the next one will be easy.
BTW vid det diodes are usually in a can. Often the can has two parts
& if you pull the top half off the diode is there. You can always nip one end
of the diode & hang a new one in on the bottom for test.
73 Zeno
LFOD !