Westinghouse H840CK15

[ohohyodafarted]

Congrats Ben! I would bet your assumption that the tube had been replaced at some point, is correct. The tube seems to test like NOS. And the fact that you found some carbonizing only on the socket at pin13, I think your assumption that this is a replacement crt is probably correct.

In addition, it is my belief that late production crt's from RCA were more likely to be free from leak defects as RCA got better at producing good leak free tubes.

When you get a chance to pull the tube, it will be interesting to see if it has been re-necked which would indicate a tube that was either rebuilt at RCA or failed QC and reworked during original production. I have seen a couple 15Gs that were obviously renecked/rebuilt/reworked by RCA. Although this is just conjecture, I think that after the original production run was over, RCA rebuilt duds to have a supply of 15Gs for RCA's replacement crt division. It is well known that replacement crt price lists showed the 15G to be available for quite a number of years.