by erichayes » Sun Mar 18, 2007 11:21 pm
Hi Jeff,
It's hard to describe the smell of either a selenium rectifier or transformer gone south, but the transformer smell is a bit sweet. The rectifier smell is pungent and choking (and highly toxic).
I'd do as Tom suggested, but before popping a tube into a socket, let the transformer operate under no load at all--not even the pilot light. Check its temperature after about a minute; if it's cold, check it again after 5 minutes. If there's no change in temperature at that point, go ahead and put a load on it.
If it turns out the transformer has had it, don't lose hope. The majority of the tubes you'll probably be testing will have 5, 6 or 12 volt heaters . . . maybe an occaisional 2.5 volter. With a little ingenuity, those voltages can be created using "junk box" transformers, or a new Hammond with multiple heater windings.
In any case, you'll want to replace the selenium rectifiers with 1N4007s. It wouldn't be a bad idea to replace the electrolytics, as well.
Good luck
Eric in the Jefferson State