i think you are out of luck ,as they haven't made that control since about the mid to late 70's .only hope is that some body has a stock pile of old part's or a spare control .it was a good unit made under license by Morse controls but western wont let be manufactured any more .
a lot of guy's liked them .i guess they liked the black joy stick better ,it was easer to take apart but i think it sucked .