Johnny:
Interesting; mine started acting up today also. Had been working perfect. Did the reset thing but no go. Didn't seem to want to GB by Fastgrab or manual. Wouldn't pick up a quarter, dime or penny on the surface but would pick up a nickle and had VDI number in the 60's. Took it outside to see if it would straighten out but no go. Came back in and changed to the small coil. Worked perfect indoors and out. Had planned to open up the connector to see if there were any solder bridges but the Phillips screwdriver I was trying to use won't cut it. Don't know if you've ever looked inside one of those connectors but the solder joints are real close together. Anyway, I decided to put the large coil back on, making sure it was snug and well seated, it started working correctly again. Sometimes I wonder about coiling the cable around the shaft because in amplifier circuits, sometimes a coil can act as an RF choke. These coil wires seem to be well shielded, so probably not. Wonder if there's only wiring in the coil or if there are other electronic components that might be affected by magnetism or static electricity? Large coil had been laying next to a large shovel blade and wonder if there could have been some sort of inductive coupling. Anyway, it's working again.
Ron