Transformer issue

Do you have a digital voltmeter?

Start by checking with an AC voltmeter between all the various combinations of binding posts on the output plate. Turn the two handles to an intermediate spot on their respective dials. See if your readings match the stamped values on the plate.

The U posts are internally connected.  If you are getting intermittent readings or outputs, remember that you can use A and either U post, or B and either U post.

Get back to us with your initial results, and we'll help you further.

Suggestions:

1) make sure none of the binding posts on the back of the transformer are loose from the case, if so some may need to be replaced.

2) if not, wait to see if the voltage dropping out happens again, it could have just been a loose connection the first time.

Yes, as Steve points out, step two, after learning the output values, would be to take the cover off. and see if there are broken solder joints or wires at the posts. But first, do step one.

Obvious disclaimer, if a transformer is suspect, it is always best to have a qualified individual look it over. A KW is a very nice transformer and properly serviced can provide years of reliable service. I wouldn't write it off. There are a few common faults that could lead to your symptoms. I'm sure there is someone in the metro area who can look at it for you - I just don't have a current recommendation off the top of my head.

And of course for your safety, if before you remove the cover, unplug it from the wall plug.  There's 120 Volts AC in there on the transformer coil and elsewhere!