I decided to break into my 1000V DC, 10 Gigohm insulation tester, today. No particular reason , just curious, as still in perfect working order. Had to break a seal to get inside, never needed repair by me or previous owners, just my adapting to 9V nicad use rather than pair of unobtainable
4.5V batteries. Made in Austria , Norma Isolationmesser 667 001 Date inside is 15 December 1965, i thought it would be 1970s Just disintegrated foam inside, compenentry like Siemens AD130, AC153 and OC75 all fine. Whenever I check calibration with a 1G glass cased resistor it is the same cal setting, no switch problems or anything else.-- Diverse Devices, Southampton, England electronic hints and repair briefs , schematics/manuals list on