Hi Wil,
I have an original 3-6PT power xfmr that someone had klooged into a '52 Fender Pro 5C5 brought into my shop. It had 500V on the filter caps (ouch!) before I removed it. It's in good shape and the exact model for your amp. $75 + shipping and it's yours. Email me if you're interested and I'll send you pics.
Neal