Tube Health Indicators?
 

Is there some way to look at the inside of a tube's neck and get a rough idea of how worn out it is?

I have heard people mention that you can see the metal or the metal cups inside become discolored, but I'm not sure exactly what to look for.

Are there specific parts that are visible inside the neck tube that I can use to approximate tube wear?

Bright silver = good. :yes:

Dark blue/ brown. = bad. :tears:

http://suzaku.live-evil.org/0222251948.jpg

What exact parts on the inside do I want to pay attention to?

Is it some particular wires, or the metal cups?

Will it all be dark blue/brown, or maybe just a section of it?

Rear most elements, nearest the pins, which has the cathodes in it.

Okay. I think I see what you mean.

I picked up this TV recently. It's a Sony from the early 70s, and it looks like total garbage. There's soot and dirty all over the inside, and there was goo all over the front of the tube and the faceplate.

I am wondering if it's even worth it to fix it up. The inside of the tube seems okay, at least it's not super discolored or anything. Is this the part that you mean?

https://i.imgur.com/I2o7bom.png

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?

Sometimes if the tube has not been used in a long long time, they have to wake up a bit by having the heater on a bit before they give a good reading on a tester, but if no shorts show, yes, a CRT tester is the best way.