If you have a DDR Solo with a deluxe pad and some of the pad lights always stay on or never stay on, then you may have bad optical relays on the lights control board. These can be replaced with a higher-quality aftermarket relay as listed above to make the lights operate properly again. First, try to reset the on-board circuit breakers (small black piece with a white pushbutton at the top) by pushing down with a small instrument like an Awl. If that doesn't fix the lights and you know that the bulbs and pad wiring is good then you should replace the optical relay for the channel that isn't working.