My erratic detector is miraculously fixed. Turns out the coil cover that had a large amount of fine sand-dirt was the culprit. It was a night and day difference. Ran the sens in manual up to 25 and had a very smooth threshold. Found some wheats and a merc that were all 8 to 9 inches. My coil cover is not very tight and this let the fine stuff in, but not being very tight makes removal to clean easy. Live and learn. R.L.