This has been covered in various posts but not in quite as "linear" a
fashion as below.

As with all situations that bring you in contact with or too-near
may-soon-be-rotating machinery, life and limb is at risk. You know that.
DTTAH, YMMV, IANAL, AC&NR, E&OE, Carpe Diem, Carpe Chuck (see below),
Caveat Emptor.

You have 5 main components: start winding, run winding, start cap, run cap
and switch.

Dead main winding or main cap is fatal to running.
Dead start winding, start cap , switch is fatal to auto starting.

Dead main winding or cap MAY give a kick at some stages due to start
winding interactions but probably not.

As  main winding and main cap are always in circuit when running, and
nothing else is, if these two are OK then once running it will run OK.
SO:

Lock students out of room so they will not see you do this :-) :-(.
Maybe one trusted helper OK.

Be able to apply power in a trice and,
Spin chuck by hand as fast as possible and at peak speed apply power.
AND / OR ((even) riskier:
Apply power & then twist chuck fast by hand.

Try this several times if necessary.
If no inclination to run it's probably main  winding and/or cap.
It should hum not necessarily quietly to itself wit power on and not
rotating.

Lifetime of components when not rotating is unknown.

A motor may be started in this manner indefinitely - 20+ (30+?) years
 operation may happen. Ask me how I know.
(Cheap drill press, bought at a sale long long ago, good value at the $,
found to have dead start circuitry after purchase. Just used it ever since.=
)

If the above does not work in any way I'd expect the main power circuit to
be dead in some manner.
If it did work I'd expect the start circuitry.
I may be wrong.



            Russell
--=20
http://www.piclist.com/techref/piclist PIC/SX FAQ & list archive
View/change your membership options at
http://mailman.mit.edu/mailman/listinfo/piclist
.