Tube Health Indicators?

[vol.2]

Originally Posted by Yamamaya42

Correct, if you look at the picture of my16FP4 you can see how dark it is there, which is by no means a tell all, but a sign of trouble, testing with a CRT tester is always best, an in my case, the tube was stone dead.

Ok. So, short of testing the tube, this is probably the best indication I have then.

It seems like this one doesn't immediately show signs of death, would you agree?