08-24-12: Atmasphere
"Sailcappy, I am really sold on the idea that the breaker is at fault. Have you been using it as a power switch? Or is the amplifier designed with it being the power switch?"
Based on the mag-breaker's rear location, the amp's remote-trigger feature, and front-actuated Power/Standby pushbutton switch, it's intended as an "actuate-and-leave it" protection device. Although, with all his troubleshooting prior to and well after Cary's diagnostic testing, that particular mag-breaker has probably been subjected to several dozens of set/trip cycles. Certain internal electro-mechanical aspects could be deteriorating, though lacking the component's specs/data information, and additional dianostic measurements, it's an educated assertion - something most experienced techs would investigate in any applicable field of electronics.
If the two filter options fail to resolve your issue, I wonder if Cary would sell you a replacement breaker. Is your skillset up to changing that component (which *should* be a breeze), or maybe your friend could do it rather than sending the amp back? Even if Cary won't sell you one, the component's mfr info/PN is probably still available on the breaker's body once it's accessed within the amp (possibly by removing the bottom panel) - thus likely availability unless a custom-spec'd option.
Frank