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.
Smoke coming from transformer means........anyone?
Found an old tube rcv. turned it on and it started to smoke. I noiced the transformer was extremely warm. Will I cause any more damage turning it on? Shiould I replaced the transformer or junk it? Anyone able to help me?