Prototype set is here

[miniman82]

Here are the changes required to remove the HV pot from the end of the convergence string, isolating it from any changes in convergence current draw. This should make sure that anode voltage doesn't jump around when convergence potential varies. Just lift the wire coming from the 50 meg resistor, move it to ground. Then take a wire from terminal 1 on the flyback (B+Boost), run it though a 2 meg fixed resistor, then to the open terminal on the HV pot. This arrangement gives you 420v on the high side of the pot, 270v on the low side. Pretty close to what I measured originally when it was still in the convergence string, which was 468v high side, 303v low side. During testing, the HV regulator works just like it should. I am able to adjust HV throughout its range from 20kv, to low enough to make the 6BD4 start redplating. For now, I left HV set at about 19kv. Tomorrow if I get some time, I will install the proto CRT and attempt to converge it with the factory 50 meg resistors in the string. If it doesn't work out, I'll play with the new ones. Here's what things look like right now in the cage.

[miniman82]

Steve reports the first attempt of getting video through the chassis, connected to a spare 15GP22. There's light on the screen, but some sweep issues have been encountered. Steve hopes to have these sorted shortly, and we might see some color images very soon.

Test setup.



With vertical sweep.



Without vertical sweep.