You probably need a replacement switch box for your OF20-SH machine. Onfloor has the perfect replacement for your OF20-SH machine. You can purchase this Toggle Switch box for the OF20-SH machine, and get the best electrical system. It easy to fix and comes with a DIY manual to work you through the entire process. You don't wanna miss out on this amazing offer as it is easy to use and durable. This switch box is the best to use for the OF20-SH machine.