Brent S

I have a 2010 arctic spas tundra spa. I've replaced the salt cell in it twice and cleaned it a number of times. I noticed today that there is no buildup on the plates so the cell is not working to generate chlorine. I checked the voltage at the round plug at the bottom of the socket the cell screws into with zero volts read. Wondering if anyone out there has a schematic of the circuit board and directions to the fuse location. Any help would be appreciated.