I would send it back or at least call Adcom to find out from them. They are the best source to ask this problem. I don't think anyone would care to purchase it with a possible future problem, and you also maybe ending up with a unsatisfied buyer ( and feedback ).
Adcom ACE 515 problem
I have a 515 that had what I thought was a bad relay (See my other post). The section that turns off power amps did not work. After a few months in that condition, it started working again on its own. Any ideas why? Ihave wanted to upgrade line conditioners and is the unit ok to sell (Provided I disclose history of unit)? Thanks.
-Kevin
-Kevin