Update: My stepper motors are fine. I temporarily got my printer working. Started working completely randomly. I discovered that the VMOT pin on my ramps board is extremely inconsistent when it comes to voltage. When it actually measures 12v, my printer works. However, it seems that anytime I plug something else into the board, the VMOT changes. And sometimes it just changes without me touching anything. When it does change it changes to less than 12v and usually stays there even after I unplug everything I just plugged in. And then it might be 10 minutes or 10 hours later before I get VMOT back at 12v. I don't know what's going on or even where to start replacing stuff. My PSU is an ATX EVGA 600B. Should easily be up to the job. Also brand new - only used in this printer, and worked flawlessly for 2 months.