I installed the diode, with a couple of 25 ohm 10 watt resistors.
Bingo. At household 121 VAC, full Raster came on. Sound on. Pin 8 on 6X5GT reads 390V. Exactly as per spec.
Raster is a bit dull, but I haven't put a signal on nor have I adjusted the 6C4 oscillator.
Should I run it a bit to wake everything up?
