Reply To: 1958 Mercury mark 10

[JACQUES]

small meters have small internal batteries and can not fully test the  insulation value a condenser.  a higher voltage is needed to  check for  internal leakage which will short out the  coil kickback voltage

at bare minimum   you can build a small  test circuit like this one.  it does not  have a voltage doubler to reach  250 v+  but should be better  than a  3-9volt  battery

Joining AOMCI has priviledges 🙂