So I decided to try that extra 19AP4 picture tube in the Zenith, powered the chassis up and with the other tube installed I only received a very dim picture that can barely be seen with the brightness control turned all the way up and the room lights turned off. After trying to adjust the Ion Trap for a bit with only a slight increase in brightness I figured the tube was bad and reinstalled the original tube that I knew worked pretty well. Powered up the chassis and OH NO, its the same result a very, very dim picture. My first thought was I might have lost much of the high voltage so I measured it, the schematic says 12KV and I measured 10.5KV on the 2nd Anode itself. Does 10.kV sound too low or is it within proper range? I also took voltage measurements on the tube socket, pin 10 is B+ and measures 371, schematic calls for 360. Pin 11 calls for 36 to 79 volts and also checks fine. Now I'm really stumped, I had a nearly perfect picture just the other day. What might cause a suddenly very dark picture? Any suggestions as to what to check for would certainly be appreciated.
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BTW, something I and many others here I am sure would like to know is, how did you find a workbench with so much cleared space?
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ps. Hey Rob, my work bench normally is not so cleared off, since it was my first time working with a metal tube I figured I better clear off an entire area as to prevent any possible arching to other objects near the tube. I was probably being a bit over cautious, but I figure one can't be too cautious with high voltage.