I'm looking for referrals on who can repair/upgrade a couple ADCOM 535 amps.
John Hilig at Musical Concepts have been rebuilding and modifying Adcom 535s for over 20 years.

Have you tried contacting Adcom? They were doing repairs as of a few years ago. They will bring the units to factory spec, but will not perform upgardes like upgrading power cords, for example.

Regards, Rich
Adcom no longer repairs their products. They will refer you to a local dealer. I was told by Adcom that their internal resources are being used strictly for R&D and future product development. (I spoke with them about checking my 5400.)
I did contact ADCOM and they gave me a couple of places who perform service. I think I will try and follow up on Drt's lead, thanks!
I'm begining to think that one the differences between high end and mass market is the willingness to maintain ones own products or just refering ones products out. High end companies take care of their customers for the life of their products. Mass market companies drop you once the sale is completed. This may signal a new direction for Adcom. Too bad.
See the recent thread "ADCOM repairs". It looks like Adcom has gone the mass market route mentioned above.
ADCOM has given up the taken care of their customer for mass market when the company was sold. If you ever heard of KEF America, The North American distributer, owned Adcom at one time. And now adcom is no longer a NJ based company.