Wiring schematic for a Forte 4a

I owned a 4a Forte' since new. For 17 years. then sold it.
It is great as is.
A Pangea 9AC power cord was nice on it.

The Forte' 4a is becoming a classic. So modifying it will lower it's value.
Just sayin'.

Just rebuild it with current and better parts. Rewire it while your at it.

I agree with both posters, it is a classic, so I wouldn't perform any circuit modifications. If you want to upgrade perfomance you can certainly rebuild it with better caps, wires, reisitors, binding posts, RCA jacks, etc.