Every time Maco made a batch of 750 amplifiers, the diagram changed. From 9 tubes to 8, from grid-driven to cathode-driven. From 2057 tubes to 8950s.
Even if you have diagrams for four or five of the versions, your unit may be a 'hybrid', wired one way in the driver, and another way in the power supply and final.
If it were a car, you could go by the model year, to tell which steering box and brakes were used on that production run. No such year-by-year guide to Maco amplifiers out there.
An amplifier like that really needs someone who can analyze what's there and work from that. Calls for the same skills as building one from scratch, more or less. That box is not a good 'starter' project. Good tech data is most important when you aren't familiar with what ought to be in there.
Oh, and I have NEVER seen a parts layout diagram for a Maco. Ever. Don't believe they ever released one.
It's a little like working on a Yugo.
73
