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

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

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

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

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