How to repair or replace a power transformer?

Hmm. Did you disconnect the transformer from the rectifier?

If not your test may not be conclusive.

It will likely be more expensive to repair a damaged transformer like that than it will be to replace it, even if the new part is custom-built to do the job. It will be handy to get some voltages from the amp that works, and its likely that you have something else wrong with the amp- its unusual for power transformers to fail on their own.

You might want to talk to Jack Elliano at Electra-Print http://www.electra-print.com/

Sorry to hear that.

You will need to get AC voltages from the other amplifier. I would run the transformer with no load and test its voltages, then hook it up and measure them again so you can give these figures to the transformer vendor you choose.

It may help to provide both transformers to the manufacturer. That way they will have a transformer they can test and one to take apart if need be.

This will likely cost you about $500 by the time you are done, just for the part. A pair of these amps are up on ebay FWIW...

Sometimes a power transformer can have design issues- such as a spot in the part where a winding makes a bend that causes the insulation to fail. That can lead to windings shorting, the transformer thus running hotter so more windings short and so on.

Sounds like you made the right move!