I have a Schwinn 103 upright stationary magnetic resistance bike. The computer died and I don't want to spend any money to replace it. Instead, I would like to change it to completely manual. So I am looking for something I can use as a gear shifter. Its job would be to pull the cable (same cable as in any regular bike) to several different position (distance range about 1 inch). Looking for recommendation which kind to get and where to get it. Have been looking at amazon but couldn't find any.