Axes no longer home/move

Hello, first time posting.

I have a gantry style mill setup using servos on three axes, controlled with a Mesa 7I96S, and using the probe basic interface. It has been working fine for nearly a year now, despite a realtime delay warning at startup, which I haven't gotten around to fixing. But that is not my main issue (maybe it is). Today, after the machine homed itself, I was unable to jog any of the axes, and then was not able to home the machine, even after multiple restarts.

I checked all the servo power/enable lights, they were all good, the power supplies were all providing the proper voltages, and the Mesa board did not have any red error lights. When running LinuxCNC through terminal and homing, the only error shown is that single realtime delay error on startup. When pressing home after enabling the machine, the feedrate changes from zero to the homing feedrate, but the tool position values do not change and nothing physically moves. After one of the restarts the position values did change, but the machine did not move, which confused me even more. Manually jogging doesn't do anything now since it refuses unless the machine is homed. The fixed-speed spindle relay can still be toggled. The servos hold their positions, but that is of course because of their integrated controllers. 

I am at a loss for what the issue could possibly be, and why it happened out of nowhere, and would love some pointers/to know where to look.
Thank you for your help!

Yes I have the original config, just tried it and the same behavior persists and nothing moves. However, the position values change when homing / jogging.

yeah that's definitely an issue. its -0.11V by default and in one direction, and 0.03V in the other direction.

Sounds like U5 ,U7 or both are damaged (these are the driver chips for the Step/Dir 0..3 outputs)

Yes, Mesa has 5V power.

Attached is an image of my U5 and U7. U7 has a blemish that cannot be scratched off, maybe a sign of damage? I looked at the onsemi datasheet for them, does one buffer control the step signals and one control the dir signals? Or is it like one controls all the positives and one controls all the negatives since one is inverting and one is noninverting?

U7 drives STEP+/DIR+ 0..3