Hello Roy,
I always get my customers to send me the following boards:-
Memory unit
Mechanism Control Unit
Selector Logic
Having these three boards usually sorts out the of the problems also if you adust the variable capacitor on the memory unit if effects the selector logic and vice versa.
If you were in the UK I would say send them to me for testing, I know that Bruce Wentworth in the USA no longer does these boards but contact him I know he recommends someone over there.
Regards
Alan
Alan Hood
ami-man
UK
alan-hood@datex.co.uk