DAC90a Number Three.

[Aerodyne]

Neat case repair, Joe. Are you sure all the valves are OK? Running on too low a mains setting will have overrun them and inevitably shortened their lives. I din't like wax-coated caps, especially not the ones found in Bush DAC90A's, so I tend to change them all - bearing in mind that they'll be the best part of 60 years old and that they do tend to deteriorate with age as well as poor storage. After this, I'd do voltage checks to see if any resistors are way off spec before checking to see if the phantom alignment fiddler has been up to his tricks. Sometimes the fault you encounter is the reason the set was discarded in the first place.
Finally, caps across IFT windings and dampness or corrosion in the RF and IFT coils can all contribute to low gain.
Just my take on things. Each to his own!
-Tony