The head (motor with variable speed drive with quill) is easily removed. Hook it up from top to a crane or forklift, make sure it is safely held.
Remove all the wires going to the head, noting their position.
Then open up the front and unscrew four 1/2" socket head screws inside. The head will come off.
I did this myself.
Bridgeport Series II Interact 2 CNC Mill ==> Disassembly For Taking Home
Then put it on a table and continue working on it.
I personally doubt your explanation, not completely denying it, but I am a little skeptical.
Prior to taking head off, you can take off the motor fan cover (it is held by three screws) and try to turn the motor by hand. Prior to this, set the spindle to the lowest speed to minimize losses in the transmission. See if it feels sandy or otherwise bad.
Also, do the fuses blow with the spindle not running at all?
i