[R-390] tube tester

[wli]

I picked up an I-177 years ago, and it has been useful to quickly check a bunch of newly acquired tubes. I think that tube testers are good at screening for internal shorts or open heaters, and not much else. As others have stressed, the one meaningful test of any specific tube, is its performance in a *real* circuit. After all, that is the one place where you want it to function. 


Roger has outlined to us how to grade performance in each location in a R390A. It may sound tedious, but IMHO it is time well spent if you want to optimize performance. Took me a long time to finally achieve that magic 30:1 ratio in the IF-audio circuitry. 


W. Li