19ap4 question
 

I have a 19ap4 I would like to sell but i am having issues with it. It has strong emissions and no shorts....
On my sencore tester you have to set the tester to gun balance even on a black and white crt and set the tester needle to a line. As far as I understand that is for contrast capabilities. I can not get the needle to move on that setting.
for every other tube I have tested I can set that function which is the step before checking emissions.
Any ideas? It is a rare tube and has good getter and emissions so it would be a shame not to be able to sell it.

The Cutoff may not be good on the tube but it might still work ok.

Do you have a working chassis you can try it in? even a 10" chassis ought to be able to run it enough to see how it looks.

The fact it's under vacuum and the cathode is lit is a good thing. My RA-109's drool for it. Ironically, what I have learned from this site is the loss of vacuum in cold surroundings is a possibility. It's 34 and sunny here and all but my "good" 15G (picture on Pete's site) are in unheated storage. Curious as to what others have to say about shipping it during Winter temperaures.

I can tell you for a fact that I had two metal cone B/W CRTs that were stored in a shed went to air. Lucky the 21CYP22 was OK.

Well, this crt came from outside in a set under an overhang. It came from a tv repair shop that closed in the 70's and was in an unheated/un air conditioned building til about 5 years ago and then was stored outside here in ohio. I do not have a set running to try it in now.

Is it really the cold that's the problem, or is it the transition between hot and cold? I would think it's more of a thermal expansion/contraction issue between the two different materials. :scratch2: I've often wondered the same thing about storing NOS glass tubes in the attic.

What does the getter flash look like? Could you possibly post a picture?

i sent a pm , possibly buying it

mike

Well, I had the bias on the wrong setting.....so crt is perfectly fine and so a videokarma member just got a fantastic deal on this tube since we had an agreement before I caught my mistake!

Live and learn....the hard way !