Restoring an RCA CTC-10 "Wynnwood".

[miniman82]

Trouble with necked tubes is you don't know if it was under vacuum when it happened, if it was the air rushing in can literally blow the phosphor off the face of the tube and ruin it. No way to really tell without rebuilding it either, it's a real crap shoot. In short: there are better candidates out there with bad guns still under vacuum, better to try those first.

[Jon A.]

Originally Posted by miniman82

Trouble with necked tubes is you don't know if it was under vacuum when it happened, if it was the air rushing in can literally blow the phosphor off the face of the tube and ruin it.

As of seeing this post I finally know why an old TV I trash-picked in my youth had that nice little black spot in the middle of the screen.