thanks for your help
i will update

for the early model ev100's that did not have the Z plug for the handset there is a door in the front that flips down and there are trimpots there to make adjustments. All the other plugs are the same and provide the same function for inputs and outputs. The screw terminals also are the same. You can check the screw terminals with wires 6 and 8 for fwd and rev signal and see if the contactors are getting the signal from the card.
I believe in your other post you mentioned it comes and goes depending on when you cycle the key switch? I would do 2 things, first pull the plugs, get some needle nose pliers and go inside the plug on the card and tweak the pins slightly with a slight twist, this will insure they are connecting, sometimes they get loose and cause intermittent issues. The other thing is to check the fwd and reverse contactor tips and make sure they are not worn or binding.
You can replace the card with an updated one if you like but before you go through that check the card outputs first and adjust those pins as i mentioned above.

I read your problem some old cards on ev100 had no way to plug handset into with made it difficulty to check you have to check each component. you could call a company called flight system give them the number of the card it is long number on the top of the card ask them if they have an up dated card with a spot to plug in handset. This would help were to start.