Dynaco ST-70 repair in Washington DC?

I've got an old dynaco and I think the can capacitor is gone. The rectifier is sparking and one channel has a horrible noise in it. Then it blows the fuse. There is a burned resistor on the motherboard in front. It's not the EL34s. I've taken off the leads to the offending channel output transformer...both that and the power transformer seem to be OK when checked with an ohm meter. I imagine it's the can capacitor...but I'd like to get it professionally repaired so I can enjoy it again. Anyone know of a good tube tech in DC?