Tube amp repairs in the Boston area?

Personally,  I would call Dan and see if he could diagnose over the phone.  It may well be something simple as you say, but get his opinion first. If he can’t diagnose it, I would recommend sending it back to him for repair. Unless the tech you know is very familiar with that exact model, IMO, the factory is a safer bet. Take care. 

If you want the best it’s worth maybe a it of travel Radu Tarta in CT has made several amplifiers ,preamps for myself and friends  not many in North America 

can match his knowledge base and engineering at Very fair prices !!

Thanks for the recommendations.  

I live in the Boston area, and I have used Jim Fuller of Fuller Sound. He works in/with Goodwin's High End in Waltham. He is truly wonderful in terms of the range of equipment he can competently work on. The costs seem reasonable, too.

Tech HIFi (he actually bought the licensing of that iconic name) in Hanson, MA (South Shore) did an excellent job with my all-tube Scott tuner recently. I think they also do good work.