Bummer...my Bryston 4BST amplifier just lost one channel

The Bryston amplifier is over 20 years old and has been my mainstay amplifier in my mastering studio for all of those years. It has been on continuously for all of that time. The left channel just went quiet in the middle of a mastering session. A good friend who is a retired electronic engineer looked at it and could not locate any problems. I have decided to replace it with a Benchmark ANB2-amplifier. See this review https://www.theabsolutesound.com/articl... amplifier/ I have heard nothing but good reviews and I know it will be the same quality as the other Benchmark equipment I own. I will get the Bryston fixed and use it elsewhere. FWIW A real bummer...