Well then, it appears you have a project ahead of you. It appears the device failed and was left sitting in a lab unit the brushes and springs got so dirty they didn't work.
1) Troubleshoot the PCB/logic to get it working (might be a very difficult journey).
2) Scrap the fancy electronics. Buy a cheap PWM controller or use an old-fashioned resistor controller to get a useable mixer.
Unless you are doing large scale preparative work, I use a magnetic stirrer. In my entire career in chemistry, I can only think of a few times that I used an overhead stirrer. Nevertheless, I do have a very old one that is controlled by a barbaric rheostat. Who really cares about the rpm? You just adjust it to what seems right.
1) Troubleshoot the PCB/logic to get it working (might be a very difficult journey).
2) Scrap the fancy electronics. Buy a cheap PWM controller or use an old-fashioned resistor controller to get a useable mixer.
Unless you are doing large scale preparative work, I use a magnetic stirrer. In my entire career in chemistry, I can only think of a few times that I used an overhead stirrer. Nevertheless, I do have a very old one that is controlled by a barbaric rheostat. Who really cares about the rpm? You just adjust it to what seems right.
