Initial Startup & Failure
Once I'd done a cleanup and reconnected the cabling, iit was ready for a power test. Unfortunately it didn't go well. Upon startup the feedback motors rotated the wheels correctly, but then the PSU started to heat up and melt. I had put a blow heater into the cab for a number of hours before starting to try and reduce any residual moisture, but perhaps I should have taken the transformer inside for a few weeks before trying.
At this point I'm assuming it's irrecoverable.
With the Transformer removed, it meant I could still get power to the dual psus on the back. Also with the monitor's disabled I was able to use a VGA adapter.
Picture was there at the start and then faded. :(
I reused the VGA driver for another project later, and it wasn't correctly setup, so some of the bad picture quality initiallly may be due to that.
I have decided to go for the computure replacement route initially to at least get something working with the hardware. I'll hopefully revisit the original hardware at another time.