We have an 85 4020. Tried to turn on the spindle today and got a "spindle motor overload" alarm. It has an upgraded drive (Baldor) which has been running flawlessly for years. The only thing I can find is fuse 9 keeps blowing. The panel says its for the spindle cooler & motor fan. I think it is keeping the drive from powering up because there is no display on the LED spindle drive display. 3 phase power thru the fuses before the drive is good.
Do you think the problem is in the fan motor? This machine has been so reliable I am puzzeled where to begin or what are common factors.