Parallel port testing

My Y axis is failing. It was working perfectly.
I'm using quadrature drive with channel A and B signals. Hal configuration "Show" indicates that the steps being sent to the A and B channels are normal. However, checking with a volt meter I find that the A channel is not responding.

Does this imply that I need to replace the parallel port board? The board has 2 ports on it and I was using one port for X axis communication and the other for Y axis .

Is it possible for you to switch the A-channel that failed to an unused pin on the parallel port?

That could get you going again, but won't answer the question "What caused the pin to fail in the first place?"

Rebooting the computer straightened it out.