Mesa 7i96s step/dir issues

I've had a problem for a few runs where my X axis has been stalling while traveling to the right, and today it completely stopped working entirely. I've traced the problem all the way back to the mesa board.

By plugging in the X axis control lines in Y or Z's control ports on the board, it functions as expected. That means its not the wiring, the drivers, not the stepper itself, but something on the Mesa itself.

I've not changed anything in the INI besides some homing offsets for quite some time and it functioned perfectly for a around 6 months prior. There has been some temperature increases, but the mesa is in cased with 2 120mm fans facing it.

Has anyone seen or had this problem before? Is there a solution you can suggest?

Sounds like maybe a damaged step/dir output.

It could also be marginal drive if you are using differential
wiring to a step motor drive. (its suggested to use
single ended drive with opto-isolated step/dir inputs
and differential drive with servo drives with line receiver inputs)

You can check the STEP/DIR outputs with a voltmeter.

 When the 7I96S is first powered up, the STEP/DIR pins will
be in one state and when LinuxCNC is launched (before starting
any motion), the states will be reversed. With no load, the outputs
should  equal the 5V supply  voltage in one state and near 0V in
the other state.
 

I appreciate the response, I didn't even know differential existed. I am using shielded Ethernet cables from the mesa to the drivers.

For now I've solved the issue by using another step/dir output and modifying the HAL to those pins.

But it does make me worried that this has happened and may happen again making the board useless for this machine if I loose another one.

Typically, if step/dir outputs are damaged is means there may be a
grounding or EMI issue, or the step/dir outputs have accidentally
contacted a voltage outside the 0 to 5V range.

If you use shielded cable make sure the shield is terminated to the
7I96S's GND pin (and unterminated at the drive end)