My 1460 just did the opposite,rotor speed would not decrease.One limit switch was sticking or the connection was not contacting.I had someone help by bumping the switch while I checked the connections with the machine not running. You don't dare turn it far without the rotor engaged but you can see if the speed adjustment motor will turn with the rotor off which is much safer. Should be a simple fix. You can get there either way from the top or the bottom but easier to see the switches from a short ladder from the bottom.