Locate the three fuses on the control panel. There is one 20 amp fuse located in the upper left corner. This controls the cell power. A 3 amp fuse is located in the upper right corner. This is the control panel fuse. The third fuse is located in the lower left corner. This is the main AC power fuse. This fuse will be a 3 amp fuse on 220V applications and a 6 amp fuse for 110V.