I have a couple propointers. Both sent in for warranty repairs at one time or another. The issue is sensitivity to side pressure. The slightest pressure will set it off beeping. When the pressure is removed, it stops and returns to normal.
I keep my Propointers wrapped in a heatshrink skin so they look like the day I bought them. Today I opened one up that became sensitive to side pressure because it is out of warranty.
The internals are clean as the day it was made. I removed the board from the case (which is connected to the coil by a long cable) and connected the battery to power it up.
I put side pressure on the case.....nothing. Next I put pressure against the circuit board......nothing. The Propointer worked as it should.
When I reassembled the unit, I got the same problem with side pressure on the case. I took it back apart and made some position adjustments on the coil cable that connects to the circuit board and reassembled.
The unit is much more stable now and I know why. The cable is long and rests near the ferrite core of the coil when the unit is reassembled.
If it is too close, flexing the case will slightly move the cable in reference to the core and set the Propointer beeping (as if it is detecting an object).
I drop mine on the ground when I have located the target so that I am free to dig/retrieve the target. While I don't abuse the Propointer, I can see where the slight jarring from the 6-8 inch drop on the ground can move the internal cable over time.
The cable must be long enough to dissassemble the unit for repairs. That means the cable must be stuffed back in to the case in front (or) off to the side of the circuit board.
It's almost impossible not to get the cable near the ferrite core when reassembling the unit.