Resurrecting a fine old meter

I picked up a fine-looking ex-Forces Bach-Simpson 635 multimeter from Active Surplus the other week.

Simpson Canada 635After opening it up and cleaning out all the corroded battery gunge, it cleaned up pretty well:

The guts of a Simpson Canada 635

The needle would only go about â…– full range, though. Carefully opening up the front showed that the corrosive goo had got into the meter movement itself:

Corrosion inside meter coreSince the meter was pretty much useless as is, I carefully scraped away at the green gunge on the stator. This freed up the moving coil, so the meter now works pretty close to how it should. Clock that dial!

Clock that dial!Simpson 635 Armed Forces Identity PlateI took the HV back off the meter. There’s no way I’m going near 6 kV with this meter. Anything over 12 V makes me worried …