My spindle drive is a General Numerics but I'd guess the fuses are similar. How often are fuses blowing? If it's just occasionally it's probably doing its job. Are the fuses in the spindle drive or are they in a separate box? I recall three fuses near the spindle drive on my recently dismantled machine...just checked they're MDX-2 which I believe is 2 amp 250V...so I'm guessing the one you're talking about is in or on the spindle drive and mine is 5Amp...so I don't think we're gonna solve this without someone with a Yaskwa piping in.