It was a really nice sunny day today, so I decided to confine myself to the shed and build this. I picked up a number of "new old stock" 2AP1A, 2" cathode ray tubes a while ago and I've been itching to do something with them. This is my best attempt at a composite video monitor using bits that I could rummage from by junk box(es).
I'm using the specified maximum rated acceleration potential of 1kV for the 2AP1A. HT comes from a little universal hybrid linear/switching, variable-output PSU (the green PCB) that I originally designed for powering photo multiplier tubes, which had to be modified a little for this application.
The cathode is tied to a fixed potential and grid modulation is used. From a sample-and-hold type DC restorer the video amplification path is directly coupled to the CRT grid. Being a monochrome display, the chrominance component is separated (with an old passive hybrid/thick film Sony "Y/C module") from the luminance prior to DC restoration and amplification. All this results in the best possible quality picture.
Don't have the time to draw out the schematic right now. I designed the thing as I went along and 90% the schematic hasn't been scribbled down.
Vertical and Horizontal raster deflection is provided by a pair of MJE340 long-tail pair amplifiers on a supply of +300V, delivering push-pull deflection voltages to the respective deflection plate pairs.
That's Mark Evans on the screen, assembling a Rover V8 - from "A 4WD is Born".