Schematic for a Valco Supro 1650t

[Needhelp]

This is a mid 50s Valco that I got in 1958, I believe it was two or three years old at that time. It was worked one a while back by a fellow without a schematic, and the end result was low volume in the guitar inputs, but lots of volume in mike input. I really need to find a schematic for for this old amp to get it back in shape. Can anyone steer me in the right direction to obtain one for this old girl. Serial # is X66392, it's a "Valco Supro Brentwood" model.
Thanks for any help you can give........Les