MY 210 GECKO BURNED!!!!!!

I bought 3 210 gecko months ago and I was very happy with them until
now. I do not use them very often. However, one of them stop working
yesterday without reason since my current and volt are very low so
they never get hot. this is my settings:

power supply type: unregulated 35v 4amps
resistor to limit the current: 18k (2 amp)
4 wire steppers (2a each)

when I power on driver the fuse in my cnc encloser which is 125v 5a
keep burning is like the driver is in short or somelike and I do not
understand how come it could happen if I do not use them very often
and I heard that they are very drivers.the other two works fine
without any problem.

Any suggestion???



Luis