marshall JCM 800 Bass series strange problem

[adaramit]

Hello everyone!

I work at a rehearsal room and we have a jcm 800 bass series that we use as an electric guitar amp. it has a strange problem. every once in a while while playing it makes a POP sound and stops working. it appears to be on and the tubes are lit but no sound comes out. if you turn it off and wait a while and turn it on back again it comes back to life. the guy who fixes all of our equipment dont know what causes this odd problem.

Does any one have an idea what's the problem?

thanks
Amit

[mac1amps]

sounds to me like a loose solder point, especially if the amp is being used in a bass rig (vibrations from the bass frequencies shaking the connection). BTW, the fact that the tubes light up (i.e. the filaments work) is rarely an indication of whether or not the tubes are "good". Filament failure is one of the rarest forms of tube falure.