Re: But what of the Serial Number??? Message #7 Posted by Alex Knight on 30 Sept 1999, 2:02 p.m., in response to message #6 by Steve
FWIW, there are at least two HP21 prefixes before 1507. I have a database of hundreds of HP calc serial numbers that I've gleaned mainly from public sales (some other collectors have contributed, too), and there are quite a few HP21s with 1504A and 1506A serial numbers. I've seen 1504As in the 50xxx-55xxx range, and 1506As in the 70xxx-75xxx range. For the 1507A range, they've gone from 09xxx-95xxx.
I, for one, don't believe that there is any exact correlation between serial number prefix and the actual week of manufacture, for Classic and Woodstock machines. As my database of serial numbers grows, one of these days I'll write an article for my web site to explain why I believe that. One easy clue is that I've opened up quite a few machines, and the date codes of the ICs inside are almost always later than the date code stamped on the serial number.
Alex
http://aknight.home.mindspring.com/calc.htm
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