The Ni-Wumph board from your Sinbad will work in Roller Disco, but you need to set the game select switches for Roller Disco - DIP switches 1-4 all ON.
And yes, you should never move display connectors with power on. The connector will get shorted and fry a 7448 or 7408 chip on your control board. (or a PAL on Ni-Wumph)