ive got popeye fruit machine it has a 78% key installed on a d sub i wish to drop it down to 70% as im using it as a savings bank been on ebay asked someone who was selling varable % key he said it wouldnt work as my machine is old, i love it so i have stripped the key and found the little circuit board can i alter this to 70% if so is there any diagrams. Also as well is there a manual for it or instructions for it. any help would be greatful....