Advice Admiral 12X12 20Z1 low contrast w/ lines

[Kevin Kuehn]

Originally Posted by Eric H

I see some neck shadow on the screen, that would indicate some mis-adjustment of the Yoke, Focus coil or Ion trap. The Ion Trap in particular can cause a dim picture.

Ion trap is for sure very sensitive. And if you don't get it right you risk depositing vaporized metal on the back side of the phosphor, which eventually leads to an area that shields the phosphor so it can't light up properly. Many folks mistake it for Ion burn, but it is not Ion burn because it's only visible when the CRT is operational.

[Yamamaya42]

Originally Posted by Kevin Kuehn

Ion trap is for sure very sensitive. And if you don't get it right you risk depositing vaporized metal on the back side of the phosphor, which eventually leads to an area that shields the phosphor so it can't light up properly. Many folks mistake it for Ion burn, but it is not Ion burn because it's only visible when the CRT is operational.

vaporized metal from what?
https://i.imgur.com/1lkZjXx.jpg

quick look at mine....

https://i.imgur.com/ydVQqjS.jpg
https://i.imgur.com/hXdGhq1.jpg

setup looks like it does in the diagram

[Kevin Kuehn]

Originally Posted by Yamamaya42

vaporized metal from what?

Vaporized anode aperture material being re-deposited onto the back surface of the phosphor.

Go to pages 62 and 84 of this pdf. http://www.americanradiohistory.com/...cs-1955-04.pdf

Tim over on ARF posted that above link in this thread, which was the first time a lot of us seen the light.
https://antiqueradios.com/forums/vie...hilit=ion+burn

[Yamamaya42]

Originally Posted by Kevin Kuehn

Vaporized anode aperture material being re-deposited onto the back surface of the phosphor.

Go to pages 62 and 84 of this pdf. http://www.americanradiohistory.com/...cs-1955-04.pdf

Tim over on ARF posted that above link in this thread, which was the first time a lot of us seen the light.
https://antiqueradios.com/forums/vie...hilit=ion+burn

mine looks correct, that is all I need to worry about!

[Kevin Kuehn]

Originally Posted by Yamamaya42

mine looks correct, that is all I need to worry about!

What, you didn't find that fascinating reading???

[Yamamaya42]

Originally Posted by Kevin Kuehn

What, you didn't find that fascinating reading???

I did not say that!

there was a bunch of old almost forgotten info in there.


I just got a bit nervous when you said " you risk depositing vaporized metal..."

and I had to make sure mine was correct, %100