Crest 8001 Pro, randomly in protect, need help


2013-03-18 9:02 am
Hi you guys,

I need some help fixing a Crest 0881 Pro amp.

When powering up, it usually remains in protect for up to 3-4 seconds and then turns active. Then it works fine for days or weeks.

Randomly, after power on, it stays for about 10-20 seconds in protect, goes active and/or falling back to protect some few seconds after. Sometimes stays in protect, sometimes recovers a few seconds later.

Last weird appearence of the problem was: Active after ~10 secs after power on, few seconds later b-ch goes protect, recovers about 5 seconds later, another 5 secs later a-ch goes protect, also recovers after some seconds, 5 secs later, both ch goes protect simultaneously, recover after some secs, and thereafter, the amp is running fine since days.

I was unable to reproduce this fault by heat/cold/shock or anything else. Unfortunately, the schematics offered by Crest does not match, the display board (where I assume the fault to be) is completely different.

Does anybody have any idea on this issue?

Best regards,