Makermade due driver board

I’m in a new makerspace were someone donated a Makermade M2. Unfortunately it looks like the z axis isn’t working. Anyone know where I could find schematics to see if it is an easy fix. We’re running on a shoestring at the moment, and I’d prefer not to buy a new driver board if I can fix the old one.

I see all the Maslow details, but not much from Makermade.

Thanks.