Hi,
Ok you need to read the whole thread on this as it turns out not all these machines are the same. The early one are quite a bit different, ultimax 2 etc. My mil is ultimax 3 version 1 so I can only say what I did and it worked for me.
First I plugged an ordinary pc monitor into the pin outs on the circuit board on the back of the CRT, sat it on a table and plugged into the wall for power. This was to test the signal to the monitors was good as the graphics cards can be a problem sometimes. I had to modify the panel that covers the monitors and make some brackets to hold the new ones in place. All the photos are on here. I used a multimeter on the pin outs on the CRT board to see which wires go to which connector for the VGA plug, made a diagram then snipped off the old connector and soldered on the new VGA plug. It was very tricky but I managed it, just be careful and make sure you are confident you have it correct. Can't go back once the connector's snipped off the wires.
For the power supply, on the PCB under the front panel there was a block connector to the right and a choice of 12v and 24v. I used a small screwdriver to push the wire out of the 24v slot and put it back in the 12v slot.
I got the monitors from these people:
Lilliput Europe
I hope this helps and please understand this is something that I did to my own machine and it worked ok but was difficult. Your machine may well be configured different. It all depends on the year of manufacture I think.
Best of luck.