I have two identical magnetic stirrer/hotplates that do not work. One will run for a couple minutes then shut off completely until I remove the fuse and put it right back in, the other does absolutely nothing at all. Looking inside, the power comes in, goes to a circuit board then the motor and hotplate. The two dial switches are on a separate circuit board. Nothing looks damaged, in fact, they look brand new on the inside.

I do not need the hotplate function, so I was thinking that I may be able to bypass the PCB's altogether and wire the dial potentiometer directly to the motor and power. Testing if the motor was any good, I disconnected it from it's PCB and connected it straight to the power cord inlet and it worked just fine, though at full speed only. I know only the basic concepts of circuits, so I do not know if I need to have any resistors or things so I don't fry the motor or switch. My question to you all is, what do I need to read with my multimeter to find out the limits of the switch and motor, then calculate what parts I may need in between. The device does say it uses a 10A fuse and is 125V. If any of you have an iPhone or iPad, I can "FaceTime" with you and check things in real time.