After replacing the electrolytics and seleniums, here's the image I get. There's clearly some interference/snow leaking in from somewhere.
For now, I've bypassed that "extra" trimmer capacitor and will attempt an alignment following the stock instructions. I'll leave the added traps alone.
Once I get this set running better, I hope to do a little experimenting with a 3JP1 (green phosphor) and 3JP12 (orange phosphor) CRT.
They have identical bases and pinouts, but there's a 3rd button anode and the anode voltages are about half the 7JP4.
I figure a little creative tinkering with the voltage divider taps will work.
