Wow. You guys are amazing... Incredible to me how you guys just whip out the matching schematic and find stuff on it. I google forever to find any odd schematic loosely related to the machine, just to learn that the relevant section isn't even in there. Thanks!
So I got some homework to do now. I found C715 on the schematic Gary provided. So my next task will be to locate a 4,7 uF / 25V on the board, watch some tube safety videos and get that thing out to test.
I watched some videos, but to be safe let me check with you - and I know it is my sole responsibility: So I disconnect everything from power and let it sit for 20min. Then I take a plastic handle screwdriver with the metal part connected to earth and touch all legs of most caps in there and also the anode under the suction cup. Then I am good to get my hands in there. Any obvious flaws in that procedure?
Also, on the nonlinearity: Yes the character start offset to the center, then progression to the right stops and even reverses (!). Then as characters proceed progression to the right picks up again positively in a diminishing fashion... The reverse part is with the extra brightness (doublestroke characters).