Hi Dennis, I have two 563C machines.  I ran one today in fact.

One of mine has a door switch that gave us problems like that, the other machine is older and does not have that.  It is a little switch kind of by your left foot along the door frame where the door shuts against it.  We had jacked up the cab to do something, and there was a loose wire.

I have had one of them loose all travel all of a sudden while I was cutting, and it was after running normally for a few hours.  After poking around on the computer screen, I got into a part where it shows all the parameters that everything should be running, like the hydraulic pressures, and the electrical connectivity.  For some reason, the values of the forward/reverse travel pressures were off.  I called Fabick and they looked up the correct settings, and I reset them and it started working.  There was also the option of doing a hard restart of the computer where all the settings would be reset to factory numbers, but I was afraid to try that because who knows how these old girls had been tweaked over the years?  

Good luck, I hope you find it.

I am missing a drivers side lower black engine screen.  You don't know where they is one for parts do you?