[Amps] a BANG in the AMP ?

[ON4MA Marc]

When a switched on the commander 2500 a loud bang whas heard somewhere in
the rfdeck.
The main fuse from the shack was out !
I got this amp cheap , look like never used.Before I switched on I did some
inspection
inside.No dust ,tubes where in place (2x -3cx800a7) .
The guy who sold ,told me there was a problem on 10m and 80m .But other
bands where ok !
I emailed Pat at commander he told me to look in high voltage board.
Not so easy because you have to remove the rfdeck.My question is ,wat caused
the bang ?
bad tubes ? How could you check the tubes ?

73
ON4MA Marc
DXCLUSTER CONCENTRATOR
visit www.on5oo.com