Quote:
Originally Posted by Synchrodyne
Quote:
Originally Posted by Maarten
Quote:
Originally Posted by Synchrodyne
As a starting point, what were probably the final Philips datasheet issues for these valves were dated respectively 1999 June 12 for the EAA91 and 1999 June 14 for the EB91.
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Are you sure those aren't the dates that Frank Philipse (a private person unrelated to the company), compiled those sheets? |
I think that thy are Philips’ own dates. I have attached the said datasheets, also that for the EB41.
In the usual Philips way, each page has its own data. I have taken the issue (or really reissue) date to be that of the final page. |
Clearly Frank Philipses artwork, that doesn't match what Philips would have used for a reissue in any way. Also, Philips Components wasn't involved in any other vacuum than picture tubes by that time and hadn't been for 20 years or so. The real Philips issue dates are those from the 1950's, FP (Frank Philipse) compiled the sheets at mentioned date in 1999.
However, for the research at hand, that isn't too relevant. I'm just trying to prevent urban legends from taking off.
Besides the dates on the pages, the dates and code numbers on the individual drawings might come in useful to establish the history of those valves. The drawing numbers (7R, 7Z etc.) would have been issued in order, just as the page numbers starting with 93. Only possible exception to that might be when a drawing was revised. 7R xxx xx could have been renumbered to 7R xxx xx.1 .2 .3 etc. I'm not sure whether Philips actually used that convention in this case or just issued a new drawing number.
From a quick look at the EAA91 datasheet, I'd say the EB91 was prepared for market in mid 1949 while the EAA91 was prepared in late 1954. This matches your findings.