Charles D St. Petersburg , FL December 29, 2019 Appliance: KitchenAid 4 1/2 Qt. Stand Mixer KSM90ER4 Kitchenaid Mixer Ksm90er4: Would only run on fast!. How to replace Stand Mixer Speed Control Plate. Ordered Speed Control Plate, Speed Governor and Phase Control Board (3 items which I thought would cover all eventualities). Parts came in four or five days and I watched the extremely clear video which accompanied the order confirmation email before beginning work. Set up on the table with good light and an hour later my machine was running perfectly at all speeds. I did not actually use the Speed Governor as the part in my machine was looking good but the Speed Control Plate and Phase Control Board sorted out all my problems. Afterward, I adjusted the speeds, but the video covered every single aspect precisely. Do-It-Yourself Rating: Repair Time Estimate: 30-60 minutes