Steve - this has helped me too - I remember shortly before I put the QRO 137Khz loop tuner into storage @ Dallas (where it sits today) that my 0-50A loop current meter was just starting to stick - wh
Well it seems that my 'closer look' (this time with headband magnifier plus a magnifying glass) paid off. I was able to locate a miniscule fragment of something between the moving coil and the magnet