[gridrunner]

Thanks Tony, well some progress. I reflowed some solder joints for the power connector and the LOPT, as well as some joints that looked a little suspect. When I reconnected the board I could see a display. it's maybe a little dim and needs some adjustment, but it's progress.

The strangeness with the co-pro board remains. The machine had the option already installed and it was working with it. Now it seems to have spontaneously failed, which seems a little dubious. I'm not sure if a motherboard jumper has been broken as the machine boots without the card and any adjustment to the motherboard, but when the card is installed - all the LEDs light and it won't produce a display. Maybe this was the fault the previous owner was referring to, as there's no display with the card installed.