Batteries and a strap for a vintage Zenith hearing aid

[Dubis7]

Okay, so the batteries are in, and I finally got a chance to try a power up. As far as I can tell, I'm not getting any life out of it. No amps across the power switch when I turn it on, and the tubes aren't heating.

My first inclination is to test whether any of the tube filaments are open. It uses two CK549DX tubes, and one CK546DX. I've managed to find the diagrams here: (https://www.radiomuseum.org/tubes/tube_ck549dx.html, https://www.radiomuseum.org/tubes/tube_ck546dx.html) but I'm having a little trouble reading them. I think those may be European style schematics, rather than American. Can anyone tell me how to read subminiature tube pins, and, based on those diagrams, which I should be checking?

Barring that, I'll be reaching out to that fellow Zeno pointed me to, to see if he has any leads on a schematic. This this uses a lot of couplates, so if any of those are bad, that may be game over for now. I'm not sure I have the skill and tools to reproduce complicated couplates in a size that would fit the small profile. I'm not sure that's possible at all, to be honest, but I'd have to see what each one contains first. There isn't a listing of couplate schematics based on the part numbers somewhere, is there? I at least have those.

I've done some more research on that band, and I'm thinking I'm going to reach out to strapworks (https://www.strapworks.com/default.asp) to see about having it reproduced. There's a little bump on the end of the strap that helps keep it in place once the front plate is on, that I'd ideally like to include in the new one. Fingers crossed they can set me up with something, they sound like a good source.

As always, any advice is appreciated.