had same problem on my puma, remove bilge vent to get to the wires. spent hour on phone with lowrance they tried to convince me it was the puck also, but i have 2 pucks on the boat & i swaped them and still had the problem. i read their self help which said to check antenna to see if it had voltage, it did. i checked main power hook up and found no fuses installed, the crimps on the butt splices were made using the non insulated side of the crimper on insulated butt splices i re crimped new butt splices using the proper crimper and the problem has gone away.