I picked up a fine-looking ex-Forces Bach-Simpson 635 multimeter from Active Surplus the other week.
After opening it up and cleaning out all the corroded battery gunge, it cleaned up pretty well:
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:
Since 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!
I 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 â€¦
Graham Green, ex-Active Surplus, tells me that the high-voltage add-on was for testing Canadian Forces tank battery packs.