Quote:
Originally Posted by Winky Dink
After checking about 60 tubes, all previously emissions-checked, I put one in the "bad tube" drawer and took 4 out of the "bad tube drawer" for possible future use.
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Threat or Menace: No way, but I do feel that back-in-the-day they were a
good sales tool!
They are more important now, than originally, as tube substitution is getting more difficult to do.
Tube testing just gives one a few more points of information on what may be wrong with a tube set.
I let the tube warm up for 5 minutes if it has been dormant for over 10 years. Then, I first test for shorts while gently thumping the tube, and if found, that ends the testing and the tube is rejected and I know to check the set more carefully than normal for signs of value change in resistors supplying this tube.
The tube is first checked on a transconductance checker. Assuming that it is not a diode, since the TC checker defaults to emission on those, it is then checked on an emissions checker. It then goes back in the set in the same socket with that information noted and will be used as an aid in diagnosing the problems. It may also tempt me to put that tube on my want list, which I always seem to forget to bring when I will be where tubes might be sold.
J.