Avo Valve Tester

[Sparks]

Thanks, that was a good help, and confirmed what I thought. I have now poked around in it a bit more and found the rectifiers. I have also checked the wirewound rheostats and they appear to be OK on initial checks. Also the small wire-wound resistances all meter OK, so I am hopeful of getting it going again.
Lunch almost ready now, so I will have to have another look later!
Bob