Sorry to dig up an old thread but I thought it was better to keep all the information in once place.
Recently I picked up a Lionel 1033 transformer for use under the Christmas tree. I cleaned it up, replaced the power cord and diode, and then tested it. The voltage across the various posts seems correct, but when I activate the whistle it makes a buzzing sound and sometimes there are sparks on either the 12 o'clock or 6 o'clock contacts from the video below. Is this accurate/safe? I posted the same question on Facebook and one response said we shouldn't even be using a new diode.
