I did a bit of research and found a way of extending that almost dead 6E5/6U5 magic eye tube. If the eye is weak or almost dead this is a simple cheap way to brighten up the green glow to the tube . This circuit increases the B+ to pin 4 of the tube using a resistor , diode and capacitor. I have included two circuits boosting the B+ from 250 volts ( original ) to + 350 volts and + 750 volts. I tried it and it works . The 6E5/6U5 I have was barely visible , but by using the + 750 volt circuit it is very green now . For long term I don’t know how long it will last but at least right now I don’t need to replace this expensive tube. Hopefully some one can come up with a cheap LED easy version of the magic eye to replace these old classic tubes. One thing , I did not want to modify the base or grid circuit to the 6E5 Russian tube types ( they are getting expensive now and by the way the life on these tubes are only 500 hours.)