McIntosh MA 6100 power supply AC leakage

This power supply has been driving me nuts so any help would be much appreciated. With everything hooked up the positive side of the amp power supply would hold steady in DC but it would oscillate in AC 37v 15v 0 37v 15v 0 etc. So I started eliminating loads until I had the board completely isolated with no loads. The transformer quit making noise but the AC fluctuations stayed the same. I then pulled the big caps out of the circuit and replaced them with new 1000-uf caps. No change. I pulled a leg on each diode and they all tested good and I even clipped another .1 uf ceramic cap across each of the diodes one at a time with no change. I have attached a photo I took of the schematic so if anyone has any suggestions or ideas I sure would appreciate it.

So the DC voltage after the rectifiers is fine, and one half of the AC goes up to 37 and down to 0. What happens if you measure both sides of the AC voltage at the same time?

it might have a dirty load switch .

You were close Pete!!! Believe it or not it turned out to be the loudness switch. Its on the same pot as the balance which I had deoxed but I guess I missed the switch

close ? nowhere near close except the switch bit ..nice fix anyway .
i just don't see the connection .