I read B5 I4 as made at Blackburn Plant, 1965, 4th week of September. It could be "1955" but usually the B5 codes mean Blackburn 1965 cuz other codes were used before 1956. I could be wrong...
Thanks Ted, I think you are right about it being a '65. (a '55 would be a metal base, no?) Either way it tested excellent at 110 mA perfectly balanced... So I am looking forward to trying this one out.
Do you guys have a link to a chart that helps decipher the codes? I've read through the one on Brent Jessee's site and one or two others, but it gets confusing.
Giving only one example (if that) and at the very beginning, then saying "...and so on." Bah! thats like saying "start with 23, and so on"
But knowing a second example helps tremendously! Thanks.
Somehow I think I was able to figure out my CV378 which is marked
HK KB/K as:
HK='52 October;
KB=Tube factory/
K=High Wycombe
please correct me if I am wrong on that one...
-Greg