1970's Fender Princeton: No Sound

[Skillet]

My buddy just took my amp on his tour and the amp stopper working after bouncing around in the gear trailer.

All of the tubes are in tact and power indicator is on.

What should my next step be in the diagnosis?

[JHow]

Your first line of trouble shooting is a visual inspection - especially since you suspect the damage is due to shock or impact. It worked fine before the rough treatment, right? So, have a look in the back (unplugged). Speaker wires hooked up? Anything out of place (i recently saw transfomer leads sliced by the chassis for amp that fell off stage)? Loose wires? You probably checked this stuff, but problems are always obvious once you find them.

Next, probably the easiest thing to damage with shock or impact is a tube. You said they are all "intact" - do all the heaters light up? Do you have any known good spares you can substitute? If so, check rectifier and power tubes first. If power amp is going you should get some hiss instead of dead quiet.

[Skillet]

Thanks JHow,

I have gone through all of the diagnoses you have listed (except for swapping out spares) and still no hissing or any type of sound. I try to fix things when I can, this may be one for the shop though.

[Enzo]

Test the speaker, or at least plug some other speaker into the amp in its place.

A very simple test is to touch a 9v battery to the speaker terminals briefly. A working speaker will pop or thump with each touch. Pull the wires off first.

And don;t trust the speaker wire and plug. With the speaker connected to the wires, pull the plug and touch the battery to the tip and sleeve of the plug. Speaker work that way?

[Skillet]

Thanks Enzo,

The 9v battery test got sounds coming out of the speaker. I have unplugged and replugged and am seeing every tube glow. What would the next step be?

[Enzo]

9v test works even through the speaker wire?

Make sure you are plugged into the main speaker jack, NOT the extension speaker jack.

After that it is inside we go. Is B+ getting through the amp? Is the standby switch working? I mean electrically.