Yesterday I shut off my TS. Had the dust collector running and one other tool also powered-up. With hearing protecting on I did not hear that the TS was still running, only saw the blade still turning. Turned off saw again but the blade kept turning. Hit the off button two more times still no help, pulled power cord out of outlet. Some info: Unisaw is model 36-817 about 12 year old. With Delta magnetic starter, 3hp operating on 220. No problem like this in its history. I can't fine anything wrong. I removed both wires from starter to motor, operated starter many times and it always returned to the off position after cycled. Checked freedom of on/off button movement on the switch cover but both are free. Starter seems to operate correctly but I'm hesitant to trust it. No idea why it stayed on. Any ideas, suggestions of anything else to look at??