Replacement Motor Speed Controller For L&R Master & Mastermatic Watch Cleaning Machine. This is a new speed controller for replacing the missing or broken/damaged original motor speed controller on these precision cleaning machines. Will work with L&R Master & Mastermatic. With front panels like the one pictured. If your machine has front panels like the one pictured and castings like the ones pictured, then this speed controller should be a perfect replacement. NOTE: These WILL work with EARLY L&R Master cleaning machines BUT you will have to either. The guide pin flush (a stout set of wire cutters should work) or. Bend the guide pin flat to the face of the motor speed controller. You do NOT do this if you are installing these into LATER L&R Master OR Mastermatic machines! Turning the knob completely counter clockwise turns power to the motor off, just like the originals do! These were IMPOSSIBLE to find in the same value as the originals OR in the proper dimensions! We are VERY proud to offer you these motor speed controllers that provide you with BOTH! Unlike other speed controllers, these are custom made both to perfectly fit your machine and operate exactly as the originals had. This particular motor speed controller is rated at 750? (ohms) and 50w (watts). These are a direct replacement to the originals! However, the mounting hole MAY need to be reamed out slightly for a proper fit. Besides that and what is noted above regarding early machines, these require no other alterations to be installed into your machine! To install your new motor speed controller, you must unsolder and remove the wiring going to each terminal of the old motor speed controller (be sure to keep track of which wire goes to which terminal). Once each connection has been freed, unscrew and remove the mounting nut. The old motor speed controller should now be free. Simply remove the old motor speed controller and set it aside. Install the new motor speed controller as the old one was. Replace and tighten the mounting nut snugly, making sure the guide pin on the front of the motor speed controller lines up with the guide hole (if applicable) on the front panel before tightening completely refer to the note above if you are installing this into an early/older L&R Master without a guide hole! Then you solder the leads onto the terminals of the new motor speed controller (again, making sure that each lead goes onto the same terminals as they were on the old speed controller). You have just replaced your motor speed controller! NOTE: The motor speed controller that you receive may appear slightly different then the one pictured. If you also need a new knob, we sell replacements of the black knob with white arrow! By placing an order you understand that it is your responsibility to ensure that this replacement meets your anticipated needs. This listing is for ONE motor speed controller only. Pictures of front panel, castings and other parts a. Re for reference only. If you have any questions please don’t hesitate to send me a message! See my other listings for more L&R watch cleaning machine parts.