Dumont RA-103

[Davala]

I'm back revisiting the Dumont. It's taken a bit of time and motivation to get it out and on the "bench". I finally got around to testing the CRT and it pegged on the grid emmisions. Now I have an idea of why the brightness was so bright even when the control was at its minimum.

Theres a few 1000pf caps that didn't look right on my cap tester, the eye on the tester didn't open as fully as a new cap does. So that got me going down the rabbit hole of looking at some other areas. I remember last time I was testing the set I had excessivly high b+. Its highly likely that the grid emmisions on the CRT might have cause that.. But shouldnt that load down the B+ instead of raising it?

A big issue I stumbled apon was v6(3rd video IF). The grid(pin 1) connects to a 3900K resistor and two coils. The resistor goes to ground. The schematic shows the resistor going to a 6800mmf cap and then to ground as well as through the 100 ohm cathode resistor.

Why would my set be wired this way? The service notes don't mention a production change...

Thanks!
Matt Davala