Weston Model 777 tube tester,, is it working?

I've had a problem with my B&K Model 667 Solid State tube tester. I'd like to get that working, but in the meantime, I pulled out a tester that I found in a flea market. That's the Weston 777-7A and if I can get it working, it will do fine until I can get the B&K working. I'm also going to clean up the Weston using a product called Kramer's Best. Please leave me a comment if you've used this and like it,, or don't like it.