My sensitive metal detector

Last night I retrieved a cardboard box from the garage
and started dismantling my metal detector to ship it back to the manufacturer.
After I had it broken down, I got a damp cloth and wiped dust and grit from the
shaft and inspected the parts. Then I thought for a moment…I hadn't ever taken
it apart this far since I first received it a year ago. I decided to experiment
a little more.

So I held the unattached detector coil in my hand,
and plugged into the batter/circuit box the long cord that is normally wrapped
around the detector shaft. I turned it on and waved it around. It seemed to
function fine. I was basically just holding the battery pack in one hand and the
coil in the other.

I cleaned the shaft a little more and put it all
back together. It worked fine.

Just now I came back from lunch, which I spent
detecting over at the park near my office. I had no trouble with the detector,
and found about 95 cents in coins as well as a little metal car.

My theory: There was some debris caught inside the
shaft/handle of the metal detector that was rattling around and throwing things
off.

I think it's fixed, but I'll be keeping a close eye
on it.