Need help with Beltron 2972-E

[sean]

The filament control is wired as a rheostat. Unless you have a load connected, you will have full voltage indicated on the meter. I always turn the filament control fully CCW before connecting to a CRT. Then I advance the control CW until I get the proper filament voltage reading on the meter.

1N4007 diodes will work just fine to replace 1N4005. Both are rated 1A. 1N4005 is rated 600V PIV. 1N4007 is rated 1000V PIV.

The power supply is a half-wave voltage doubler. The voltage output will be about twice the peak voltage of your AC line voltage.

The schematic you are referring to is probably the one I drew up for my unit. Judging from the build I would not be surprised if there are differences between units.