Broken tube in guitar amplifier?

Question

Hi, i have a peavey 5150 and its not working properly...when i try to play thru it i can barely hear the guitar at all, im thinking one of the tubes is blown because it is really old. is there a way i can tell by looking at the tube if it is blown or not? also there is a spring like noise whenever i shake the amp a little bit, i think that is the coil for the reverb unit? is this normal for it to be making that sound when i shake it a little bit?

Answer 1

It is normal for the reverb spring to make a noise when you shake it.

Turn the lights out and see if you can see an orange glow in each tube.  If a glass tube has no glow it is burned out.  Some tubes are metal and you can't see the glow.  If you have any of those you leave the amp on for a few minutes and touch the tubes with your fingers.  They should be warm or hot.  If they are cold they are probably burned out.

Even if they glow and are hot they can still be weak, it takes a tube tester to prove that.