I read that in the days of computers that ran thousands of tubes the most economical method of maintenance was not to wait for a failure to occur, but using statistical charts of a group (like 100) of tubes' operating life. Thus a group of tubes would be installed on the start date, and...

This is an old thread, but you say you found a little guide for the JAN tubes. Is that something that was just put together as a simple reference, or was it published somewhere? If so, could you provide a title, or where it could be found online? I am trying to find out what authority made...

That is exactly what I have found, and the reason I am still looking anywhere I can think of for more information. Most of what I find is nothing more than repetition, but practically nothing that is original. Still, I keep looking.

Thank you for the link. I believe the letter C was in use since the first World War to indicate either Contractor or Commercial type. Still, it does not explain the process or authorizing document that was used to create the letter assignments. Thanks again.

My main interest is antique radios, including military. There was an old thread regarding JAN tube designations, saying JAN-CRC could be shown as JRC, JAN-CRP as JRP, JAN-COZ as JOZ, and so on. Does anyone here have, or can refer me to, an official document that explains this? I have seen...