I used to work at AC/DC Electronics in Oceanside, CA and we made our own transformers and power supplies so I have seen how transformers are made from tiny to ones that were lifted by forklift.
I have one OT that failed probably my fault not sure, I don't remember being forgetful or careless. But then again my memory isn't what it used to be.

I'll keep it on the shelf to remind myself what $80 of junk looks like. I wrote BAD on it this time since I installed it in a new build only to find out oh yeah this was a bad transformer.
Mark