Built a tachometer transducer using a Hall Effect sensor. Has worked well many
years but now is failing. Have discovered that the Hall Effect sensor tends to
"stick" on, even when no magnetic field around, as long as power is on.

On the assumption it's not the hysteresis circuit inside the device, I tried
degaussing the sensor. No success so far. Anyone ever heard of this happening
before and anyone got a fix? Could make a new transducer with a new part, but
the whole thing is potted in epoxy. If there's an easy fix, would like to try
that first.

Thanks,

Mike Palmer
Excellence in Ergonomics