pentair pool pump problem

[bsfixit]

I have the exact same problem at this thread on this forum " http://www.poolforum.com/pf2/showthr...r-pump-Problem "

the motor hums but will not start. I let it cool down, still no go.
The impeller turns freely as does the pump motor shaft. I have 125 volts from each line to to each load wire. 250v total on both lines into the timer and out. The capacitor looks fine, no leaks , no bulging of the can. When checking wires into the capacitor, I have 125 on one lead to neutral/ground and only 27 volts on the other lead. before I try to inspect the windings what else can I check? this pump is only 3 years old. The previous pump did the same thing.
Any help would be great..
Thanks
Bsfixit

[PoolDoc]

Did you do the rough and ready check of the cap with an ohm-meter?

I snatched this from
http://reviews.ebay.com/How-to-test-...00000008774400

Be careful when shorting the cap -- don't shock yourself. Be sure the power is off! But, remember the cap itself can shock you.

Remember that this is a very approximate test -- a cap that fails is dead, but a cap that passes may not be OK.

"1) Discharge the capacitor by shortening its leads. that is - use a wire and connect the leads of the capacitor together. this will discharge it.

2) Put your multimeter in the high ranges 10k-1m

3) Connect multimeter to capacitor leads(observe the polarity if electrolytic). at soon as the leads make contact, the meter will swing near zero. it will then move slowly toward infinity. finally the meter would come to be infinite ohms because the capacitor is being charged by the battery of the multimeter.

4) If the capacitor is bad, it will go to zero ohms and remain there. this is called a shortened capacitor

5) In the case of an open capacitor there will be no ohmmeter indication.

6) Some capacitors have a low dielectric leakage. you will know this if the ohmmeter comes to rest at a point lower than infinite. test a known good capacitor of the same type to be sure.

PS: This test works for large capacitors. Tiny capacitors can only be checked with a capacitance meter, or by using them in an AC circuit and checking for variation from calculated voltage drop."

Ben