Nick it has happened to me with Chrome I have already sent Lee a PM to let him know that it has reoccurred
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If your PSU doesn't have all the right voltages it isn't the right PSU for the job, you could add a separate -5v fairly easily, but have you asked the manufacturer how much for the correct PSU for the job?
I think you need one of the older type ie AT not ATX http://www.ebay.co.uk/itm/AT-PSU-WOR...-/142163387623
see this at the bottom of the page https://en.wikipedia.org/wiki/Power_...nit_(computer)
Either the video card, or the video card is getting junk data.
You're probably better speaking to your board repairers, as now you know what the main problem was, and the machine is now doing something, it may help them track down what has been damaged.
Have you tried asking over on Practical Machinist forum?
If you're going find somebody online who knows about these machines, then that's the place you're likely to find them.