@hilde45 Any competent tech can service these things. In particular, Bryston has the world's best support for their gear with a 20 year transferable warranty. Mind you, an 80's vintage Bryston will be out of warranty, but they'll be able to service it.
Some years ago I picked up an 18 year old Bryston .5b preamp. I shipped it off to Bryston. They did the repair, threw in a new power cord (it was pig-tailed on), the shipping carton, and return shipped for free. Wow...
There's a Bryston BP6 preamp for sale on US Audiomart, for $850. Can't go wrong and it should still be under warranty.
One more thing. Bryston takes a back seat to nobody. Excellent quality.