You are going to need a 1.5v battery (any AA,AAA, or C battery will work) and some lengths of wire. E stop the machine before touching any wiring of the spindle.
Before you remove any wires from the plug to the spindle, take a picture that shows what wire goes where.
This will be needed when you rewire the plug.
-Unplug the 8 position green plug and remove the 301(+5V), 302(SV), 300(COM), and 306(EN) wires from it.
-Take a small piece of wire and fasten one end in position #5, where the 306(EN) wire was.
-Take a longer piece of wire and twist one end to the free end of the small piece of wire and fasten both in position #3, where the 300(COM) wire was.
-Take a another longer piece of wire and fasten one end in position #2, where the 302(SV) wire was.
-Make sure the spindle is clear of any body parts/tooling. Bring the machine out of E-Stop and press the reset button in PathPilot.
-Touch the longer wire from position #3, where the 300(COM) wire was, and hold it to the negative side of the battery
-Touch the other longer piece of wire from position #2, where the 302(SV) wire was, and hold it to the positive side of the battery.
If the spindle driver is good the spindle should start spinning in the 2600-3000 range (High Belt) and the spindle driver LCD screen will read numbers in the same 2600-3000 range. If the numbers are zero and the spindle is not spinning then the driver is bad. If the spindle driver is showing numbers in the 2600-3000 range but the spindle is not spinning in the 2600-3000 range (High Belt) or not spinning at all, check the spindle motor to see if it failed.