When I was a kid I had an RME69 communications receiver. The rectifier tube had died on me and, knowing something about electronics back then (but not a lot), I removed the glass envelope and wired a pair of 1N4007 diodes in to the exposed base pins.
It worked beautifully for about five minutes, then all the electrolytics blew up. That was the bit I hadn’t known! It was good to see in your advert that the suppliers warn users about that!