Princeton Reverb dead. Help.

EdGrip

I've got a 70's Princeton Reverb that I bought earlier this year. I recently installed new transformers, for a laugh, like you do. Now it won't work.

Voltages from the mains transformer are all present and correct, but as soon as you install a rectifier, weirdness starts happening. The filter caps (new ones, I installed them shortly after I bought the amp, but I was playing it for months before the new transformers) get hot, and then there's a .....snap........snap........snap.... arcing sound. And then I turn it off in a state of misery. I've been through it and through it, looking for wrong connections, dodgy socket tags, but to no avail and I can no longer see the forest for the trees. Different rectifiers have been tried.

Do these symptoms sound familiar to any of the techs here? I'm at the point of taking it to a tech, which will be a blow to my considerable ego. 

All thoughts welcome.

 - Ed

octatonic

This is going to be very tricky to diagnose virtually.

ICBM will probably be along soon with a bunch of advice that disproves this but otherwise I'd get it to an amp tech sharpish.

[Deleted User]

EdGrip;1598" said:

I'm at the point of taking it to a tech, which will be a blow to my considerable ego.

That's nearly as bad as having to read instruction manuals - something no man wants to have to resort to....

ICBM will know what to do.

octatonic

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koneguitarist

Does the arcing sound at all levels ? And have you checked the little resistors above power valve bases ? Also did it work at all after you fitted transformers ? The more info, the easier it is to work out what's wrong, but like others have said ICBM will have a good idea I expect.

EdGrip

The arcing sound is just coming from the chassis, not the speaker - there are no audio valves installed at this point, only the rectifier (I installed them all the first time I started it up post-transformer-swap, and the same thing happened. So I'm leaving them out of the amp until I know what's wrong.

No, it didn't work after I fitted the transformers. I know, I know, I should've fitted them one at a time. As I say, the voltages from the PT are all where they should be, so I think I can rule that out as a problem. So maybe a fault within the OT, or with my wiring of it (though as I say, I have double- and triple-checked my wiring, and the wiring in general. I'm no longer in a good state to spot errors. 

ICBM

If it works and gives all the right voltages with no valves in but starts arcing as soon as you fit the rectifier valve, have you wired the rectifier valve socket correctly? The two red HT leads should go to pins 4 and 6, and the two yellow filament leads to pins 2 and 8, plus the red wire to the filter cap on one of them, usually 8 but it doesn't matter.

If you definitely have, remove the red wire to the filter cap and temporarily connect a very high voltage rated (1000V preferably, if you have one) non-polar cap of any value from there to the chassis, and measure what you get... assuming it doesn't arc!

Report back before proceding further .