Smoke coming from transformer means........anyone?

The Varic method should be used with an AMMETER in the line to the DUT (device under test). You monitor the current, and if it starts to swing high, you kill the power...

If the transformer smoked (presumably the power transformer) it is almost certainly toast.

The output transformers are probably worth saving along
with the tubes. Build yourself a nice DIY tube amp! :- )

You failed to mention the make and model.
Is it an older SAE? (Smoke And Explode)

The variac method is the very best method for new (weeks or months in the box) and old, although a switching power supply will be toasted by doing this-not a problem with vintage gear.

Wasn't that a Deep Purple song from the '70's..."Smoke on the Transformer"? Happy Tunes!

Brian- thanks for the laugh!

The Variac method doesn't work so well if the unit has a tube rectifier. The tube rectifier won't really conduct until the filament voltage gets close to specification. This point will be somewhere around 75-80 volts AC input. At this point you put about 60% of the B+ voltage on the caps. Better than full voltage, though.

Yes, a Variac is a needed for vintage gear that has been out of service for awhile and/or recapping a piece. I am in the market for good used one right now. As Clueless mentions the caps can hold high amperage charges for long periods of time and you need to learn how to drain them properly if doing the work yourself. I have been shocked through one hand, on through the chest and out the other hand by equipment that has been powered down for weeks. These were "not" Martha Stewart moments, take care and caution.

Lolo- The transformer may still be good IF you powered it off in time and don't repeat the attempt until you have located the real problem. It is likely that the power supply caps have failed with age and are acting like resistors to ground rather than caps. Sometimes they can be "reconditioned", but more often should be replaced. Whether or not it's worth the repair expense will depend on the make/model and condition, including tubes. You could have a nice gem if you can locate a tech willing to give it a decent inspection/estimate for repair. Good luck

Lolo: Be careful, even if its not plugged in tube equipment can carry a wallop!!! Caps can and will store high voltage. High Voltage!! If you are not familiar with tubes/voltage I would forget about doing it yourself. If someone knows more about exactly what you have they may correct me, but better safe than sorry.

We like you the way you are.

Sincerely, I remain

Cut the output of the tranformer and plug it back in,if it still smokes you found the problem. I found an old philco radio (vintage 1937)in a customers basement. I bought it for $50 and took it home. Everything worked!
Tim Flemke

They put smoke in at the factory, you are not supposed to let it out!

Probably the tranny gave, and depending on what it is, probably not worth fixing, unless it is of collector value or such. Since you did not tell us what it is, can't help you there. You might want to keep the tubes depending on what they are. Good luck