PMDX-126 J4 Port not operative

[Gallen66]

I have a pmdx-126 BOB connected to an ESS. Apparently, output pins 2 & 3 from port 1 stopped working. I checked wires, motor and driver by switching everything out and all were working properly. I moved the output to the motor to J5 pins A & B on the BOB and port 2 pins 1 & 14 on the ESS and the motor moves now, but only in one direction.

[12strings]

The issue may be with the 126, or it may be with your driver.  Or both.  If you have a volt meter, measure the voltage on the direction signal (J5 A or B, which ever it is).  Jog one direction (then stop) and then measure the voltage on the PMDX-126 screw terminal.  Then jog the other way (and stop) and then measure the voltage again.  It should change from close to zero volts for one direction to close to 5 volts for the other.

If you don't see those voltages, disconnect the step/dir wires from the 126 and repeat the experiment.  Do you now see close to 0 and 5 volts?

Try connecting one of the other motor drivers to the same 126 pins (ex. J5 A and B) and see if it works.  Then try the known good driver on the original 126 pins (2 and 3).