I read about your problem. I have a 16" green one that is impossible to
find. I called the manufacturer today (Can You Imagine), they no longer
make the size I have nor do they sell just the black box located on the
back of it. I have had mine for about 3 years and it works sporatically. I
believe it is in the switch that turns it on and off, I will be taking it
apart tomorrow to find out. I did find a website that sells the black
boxes for all sizes for $30.00,it is made by the same company that made
ours. If I discover that I can not fix the switch I will be ordering a new
box. Yes they run around $100, the one I have cost the person who gave it
to me $175.00, so I am definately going to fix it. The website that has
the boxes is: www.strattman.com. They have some AWESOME custom made stuff
that I wont even dare to call them and ask for the price. Good luck, I
hope you get yours working becuase they are definately very cool to look
at.