You don't happen to have any 6JS6's do you?
I have been trying to get my old ham radio transmitter back on the air, and can't get much power out of it. Its old and uses valves. I am thinking I may have one that has gone bad.
I was actually just researching how to test valves yesterday. This topic came up at a good time for me.
My dad has several of those suitcase style valve testers in his basement. But as Rolf said, I am sure they need some TLC before they are going to work again.