I picked up a great old Tripet 630-PLK VOM at a ham fest for $10. Everything works OK except it needs a NEDA 210 battery for the high resistance ranges. The best price I could find on this battery is $30 plus shipping. Call me cheap but I find it difficult to plunk down nearly 40 bucks for a battery that I will not use all that often. My idea is to use a 9V battery and an oscillator-charge pump or toroid step up and rectifier arrangement to deliver the 50 microamps needed to move the needle to full scale. Any thoughts , comments suggestions before I begin this journey would be appreciated. Circuit suggestions welcomed.

 

if yoou have room, series 3 regular 9 volt batteries, that 27 volts will be close enough

 

How about just snapping three or four of these

in series...