I have done this before but had to do another one today, this is a discussion and lesson on how to , not for sales etc. I dont like doing them and dont have the extra time , so if ya want one i can sell you a new Vertex unit ( .36 MFDs with lifetime warranty) perfect for the helment coils etc....and you can do it yourself.
I cut apart a old vintage condensor for the early round top three hole coil. Note the terrible connection at end of condensor and side slide strip ( ball of tin foil in end for connection)
This one was still damp inside and may have worked very well ????
Use a little flux to solder the ground connection between vertex and old case ... I use a 8/32 allen to allow me to use a wire connection inside the coil housing , just ike stock. Roll wire into coil and its a stock looking condensor.....
Never seen a defective Vertex Mag Tech condensor.......???