Cause for concern -- scorch mark in tube

[dsavitsk]

I have a 5842 that has what looks like a scorch mark in the silver on the top. It still works fine, and I have no idea how long it has been there. I attached a pic, but it turns out that taking a picture of a silver thing is hard, so it actually looks worse in real life. I am running it way under its limits. Do I need to worry about this at all?

 

[sorenj07]

it should be fine. it's probably where a tiny bit of loose gas reacted with and bound to the getter. it's just doing its job

 

[SY]

I have quite a few tubes that look like that, new out of the box. They're all fine- I suspect that it has to do with the specific gettering process used in manufacture.

 

[arnoldc]

Both my Amperex and Raytheon 5842 looks like that, while my WE 417A does not.