I'm stumped 2 days ago I loaded my r2e3 machine and have been doing it for 20+ years

today I can no longer load it

I have 4 machines and all react the same
2 computers with pcplus software

they no longer connect in the edit mode
the computer waits for the machine to send the boss 8 signal but does not come through at the *

I have tried all in 2 computers that worked 2 days ago

I checked the wires and they look good

any ideas will help