I've had a Hobbycnc EZ board for almost a year, which during this period it was working fine until a couple of weeks ago when the X axis motor stopped working. I checked all the connections and they seemed fine. I checked the screw terminal voltage and for the Y axis it was 0 volt. I concluded that the Y chip was gone.

I ordered another chip from HobbyCNC, I replaced it and it worked fine for about 3 minutes, and then it died again. No smoke, no popping sound, no sign whatsoever.

I have a decent size heatsink with a fan mounted on all 3 chips. the heatsink has a thermocouple connected to a digital temp. gauge, so I rule out heat as the culprit, and the fact that It worked fine for almost a year and then it suddenly stopped working baffles me. X and Z axis are working fine.

I read some threads of HobbyCNC board users with the same problem, but I found no concrete reason for this failure. Any ideas?

Thanks,

Gustavo