Repaired:

Well I got hold of a manual. After some investigation it turns out to be a Nichyo controller. I was able to download a manual and found the faults.

There was one fault that blew a 10 amp fuse that was caused by wiring that had rubbed of som insulation and was shorting.

The other problem was no forward traction. This was incorrectly displayed as being TR16 and TR26. With the manual's help we found a darlington transistor whose output was blown open.

(Kinda hard to detect with a tester as the normal transistor test always gives a different reading on the collector of a darlington than the on the emitter. The nearby circuit resistance made it look like it was ok. Once it was out of the board and remeasured, the collector was completely open.)