Just wanting to let people know about the success I have had in getting my Mitsubishi mm30cr excavator going. I had the same problem as most that the controls had locked out the dipper, boom, bucket and slew, but the tracks and front blade still operated. The problem was the controls, they consist of 4 micro switches and 4 potentiometers.
The problem on my machine was that one of the potentiometers failed which inturn locked out the controls. I finished up replacing 3 of the potentiometers, adjusted the slop in the controls and then adjusted the micro switches and potentiometers. The machine works perfectly now, I suggest you get a forklift mechanic with an expertise in electronics to look at your machine. It would seem the forklift mechanics have a lot more to do with electronic controls. You can do it yourself once you know how to adjust the micro switch and potentiometers to their neutral position. Hope this is some help or it gives you a direction to start looking at your problems.
Regards treviftn