David,
Before you give up on those Scotty plugs try this.
Turn your battery power off to the plug, use a screwdriver to close up the two pos stainless tangs in the middle of the female outlet. clean up the brass male end with emery paper/ sandpaper, then lift the 5 or 6 (cant remember) brass neg tangs around the plug a little with your screwdriver.
Just did this to mine the other day and they work great now

.
Cheers... Tyee.