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C16J Tube Anode Condition

metal4130

Aluminum
Joined
Nov 24, 2013
Location
New Berlin, WI
Hello,

I just purchased 2 C16J tubes off eBay. I received then and am concerned about the condition of what I believe is the anode. I tried to snap some pictures of it. It seems like the metal has vaporized away?

Question is are these okay to use and what would have caused this to happen?


IMG_5968.jpgIMG_5969.jpgIMG_5970.jpg

Thanks
 
It took a while for me to get to one of my tubes and photograph it. It is a poor picture, hand held without flash because I didn't want the reflection. Note that the lower disk has a grille, almost like Venetian blinds. This is the control grid that controls firing. Yours seems to be melted away. In normal service, the grid is held negative, blocking electrons from getting through it. When the tube is fired, the grid only gets a short positive pulse. I would guess that someone has put a positive voltage on the grid with enough current available to melt it. If that is the case, the tube is useless.

Bill

IMG_2334.jpg
 
At first I thought it was just some getter flash. But after a closer look, it looks dubious due to where the vapor deposit actually is.

I suspect abuse.
 
The tubes are argon filled. The ones I have do not have a getter. Look at the second ring. The grid is melted away and you can see beads of metal on the edges of the remaining material and it is melted unevenly.

Bill
 








 
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