Help Please with computer on link belt 3400 Q

I bought a 3400 q a few months ago that had been sitting for several years. it was parked because the stick was badly broken and supposedly no other issues. The computer was replaced not long before when someone used a welder to jump start it, killing the computer. Now i can get no response out of the computer. its getting power at the 24v supply and from the key switch but nothing out except for two ~5v signals i haven't traced on the schematic.
I can give the monitor 10v and it will come...

Help Please with computer on link belt 3400 Q

Help Please with computer on link belt 3400 Q