On a similar thought, I had read years ago that pickup magnets could loose their magnetism over time. They could be recharged by equipment that would be used by people that repaired speedometers back in the day. The article was referring to guitar pickups (humbuckers?), I have never heard anyone refer to bass pickups having this issue. Any thoughts? This equipment is likely obsolete for todays speedometers but may be repurposed for pickup repair........... If it works.