Eric, you can skip the recap, and scroll to the conclusion.
Let me recap from the beginning.
A few days ago the washer began to miss the drain / spin cycles intermittently. One time it work fine. The next time it wouldn't. The agitate cycle always works, both slow and fast.
I replaced the timer. No change. Then I noticed that when the spin cycle failed to start, I could hear a hum. No other sounds, just a faint hum. When I lifted the lid, the hum would stop. This indicated that the lid switch is working. The hum sounds like a motor trying to start. Once in a while I would see a very brief surge when it should have begun to spin.
Because the only problem seemed to be getting the drum to start spinning, I changed out the start capacitor, hoping that the motor only needed an extra starting boost. No luck.
When we tried to wash a load of clothes, sometimes it would make it through successfully. Other times it would open the drain but not spin. In this case I would let the motor cool, disconnect/reconnect power, then attempt to start where it left off. After a few attempts, it would work. But then the rinse cycle might run ok, or not. Same drill to get it to complete. Each day it got worse, so we finally gave up trying to wash a load.
Currently I have the cover on; I had if off only to replace the capacitor, so I haven't been watching the coupler or the clutch. But because it had recently run full speed in the drain and spin cycles, and agitate always works, I don't think there should be any issue with the coupler.
Conclusion Update this AM. Per your question, when the tub should be spinning, absolutely nothing is moving. The hum remains, apparently from the motor.
I then checked the brake and determined that it wasn't allowing me to turn the basket. Per this link I applied silicone to the brake, and it freed up the basket to allow a free spin (previously it wouldn't).
http://www.davesrepair.com/DIYhelp/DIYddbrakelube.htm But.. no cigar. I ran the second rinse from the beginning. Agitation is ok, but the drain spin won't kick in... just a hum. No movement anywhere. With water now in the basket, I can barely turn it.
Then I replaced the new timer with the original (I'll return the new one). And what a surprise, the washer is working! I'm checking all the cycles, but so far it's looking good!
As they say, go figure!
Thanks for your questions and attention. I appreciated the guidance and having a sounding board.
Tom