Why does the Off/On switch not function?

William, the first thing you want to make sure off is that you have power going to the printer. Check the cord, make sure it is in good shape. Use a multimeter to check for continuity. If the cord is okay, it is possible that it is the power supply for your printer. You will have to disassemble it. Perform a visual inspection, check for any burned components, check the caps for leakage and bulging. Use your multimeter to check for power out on the power supply.