HF oscillation or DC trip @ power amplifier

[fgchong]

I am using Reference 10 for about 2 years and lately I have this HF oscillation or DC trip @ one of the channel of the Goldmund power-amplifier (either the Telos 250 or 1000+). Fault intermittent i.e. resumed to normal when I reset the power amplifier. This has being going on for a couple of times and each time it trip, the speaker cut off with exploding sound (I am using Alexia).

Send the set to the local agent but their technician could not locate the root of the problem as the fault did not occurred even running for almost 500 hours.

Just wonder any members here have the similar experience to share.

Thank You