In that case, take the remote apart and examine the circuit board in the area of the on-off button. They usually use a carbon impregnated button bottom that contacts the circuit board when you press it. Gently clean the circuit board and bottom of the button with some isopropyl alcohol and a cotton swab. If that doesn't fix your problem, then the button and/or circuit board is probably worn beyond repair. Also look for cracks in the copper traces on the circuit board, this is pretty much a death sentence for the controller. If you see any corrosion or evidence of liquid egress, clean well before reassembly. Baking soda paste can be used to help neutralize corroded tracks, but you're just putting off the inevitable at that point.