Thanks all for the ideas, I am aware this if this is to ever power up and show even raster I will need hard documentation, or extreme hard core luck!
I am hoping, that, as with similar headsets of the time, that the 'control box' is simply no more than a signal distributor, allowing for external monitors, single input feeds and, in some cases, video conversion from svideo / pal ntsc etc.
Sugnal wise, I expect the headset itself to conform, to the specs in this document:
https://www.mindflux.com.au/products/keo/Proview%2030.pdf
So far, I have confirmed that pin 11 of the AD8004 chip connects to ground, which is the same ground as the metal around the mounting holes and the other wires marked as ground on the picture. This does not directly correlate back to the white wire, but there is a path there of fairly high resistance.
If I can get a blank raster, or at least the condensers for the backlights to fireup, I think the other wires should fall into place quite easily, depending on any built in sanity checking, a single colour and a single sync should be enough to get some feedback
The black wire, when tested on pin1 of the AD8004 chip and +ve parts of other components seems to 'pip' that is the resistance quickly builds up from very low=> to very high - within a fraction of a second.
I'd love to get my mitts on the control unit for an afternoon
- there are still some left for sale at DOTMED.COM (Search for vista medical, or stereosite) but these seem to be the final hard core holder outers, who won't part with the gubbins for less than the shirt off your back, even though it's pretty worthless to anybody but hobbiests.
I think I'm gonna start pumpin some juice in and see what happens.