My Excalibur 800 started to chirp every 15 seconds. Then the threshold would continue to increase on it's own. I could at first adjust the threshold to control it but the it had a mind of its own. Then it just died. I only had the coil in the water when this happened. The control box didn't get wet. I have two batteries and tried the second battery thinking maybe dead or weak battery but wasn't that. This machine worked perfect last year. Only ever used in fresh water. Does anyone know where to send these in for repair?