I used the same Lyman/Ohaus D5 for 43 years, and then one day I couldn't get the beam to center. Maybe it was a fluctuation in the earth's magnetic field, maybe something else, I don't know. I set it on a shelf and started using a PACT electronic scale that I bought a few years ago but had never used.
Then one day I happened to glance at my old scale and the beam was on-center, dead nuts. I have no idea why. But, I'm still using the new electronic scale because the digital readout is easier for the old eyeballs to read.
