Quote:
Originally Posted by bandersen
Hmm. That's a good question. I'm not sure. Need to review the schematic first.
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Ok I applied 15vdc to the cathode and g1 and it works great now I can tell new from used weak, tried different heater voltages and was able to determine new from weak. Thanks for that info wasn’t sure it could be done. The cut off feature won’t work and it shows short on g2 but that’s ok I’m just interested in the emission of the tube. Did a comparison between a 7jp4 and 3fp7 both have the same gun the 7jp4 @ 6.3v was 340 on the scale and the 3fp7 @ 6.3v was 520 on the scale the 3fp7 is new. 7jp4 is a bit low don’t know how long that would last, wondering if running it would just turn dark and that’s the end of the tube.