I used the machine this morning with no problems! Even found a 1913 Barber dime about 8 inches down. Tonight I used it again and when pinpointing the machine was giving off a crackling sound, any suggestions or causes anyone can think off?. I'm new to the Equinox 800 and was running Park 1, factory ground balance of 0 with tracking on, 50 tones and sensitivity at 20. I tried a manual ground balance and a factory reset with the same results.