Un-potting the output transformer and preparing the cans
This amp came with just the output transformer; the power transformer was missing. Due to the overall condition of the amp, I was not comfortable trying to reuse the existing output transformer, plus the wires looked to be in pretty bad shape. That meant I would need to remove the OT from its can so that I could repot a new one in it. Fortunately, I also have a spare can here that I will be able to use for a new PT.
I had un-potted a power transformer about a year ago. While it was somewhat messy, not to mention smelly, it wasn’t too bad of a process. Removing this OT from its can proved to be more difficult, however. Since the OT is smaller than the PT, the transformer had small blocks of wood wedged on 2 sides to keep it centered in the can.
Melting potting compound in oven
This made the transformer much more difficult to remove, since it did not just drop out like I expected. Once I discovered the blocks of wood, I was able to pull them out with a pair of pliers. This allowed the transformer to drop out as I had been expecting it to, but not before I had created a bit of a mess with the liquefied (and extremely hot!) potting compound.
I cleaned up the 2 empty cans and decided that this would be a good time to give them a fresh coat of paint. I had originally planned on using a black, crinkle finish paint but then I saw something different at Home Depot. It was a black, textured-finish paint from Rust-Oleum (7220 Black), so I decided to give it a try. I was very pleased with the results! To my eye the texture matches the original, subtle texture of the cans quite well. I’d like to be able to use it on the tube cage too, but I’m afraid it wouldn’t hold up well with the heat from the tubes.
Everything is now ready for re-potting the transformers; I’m just waiting on new potting compound, which should be arriving today.