I have several A110 VCO's, four of them work great and
compared with the A111-5, track and tune so that when range
is at '0' the octave is the same as the A111-5.

However, I have three more A110's which are about 3 octaves
lower. I have to put the switch at '+3' (even though it stops
at +2) to get the same pitch as the other A110's. They
also dont track that great.

All three A110's have the same issue.

In the '0' range position the frequency is way too low,
probably a few 10's of hertz, and its below audio range.

I'm guessing I need to service these modules and tune
them. I've plenty of test equipment, scopes, etc.

Just wondering if there is a guide or service manual for
this module

Thanks.