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New-to-me HP-71B
11-26-2019, 12:00 AM
Post: #21
RE: New-to-me HP-71B
(11-25-2019 03:12 PM)rprosperi Wrote:  Since I've been collecting SN/Version info that folks have posted here, these are the units bordering the ROM version changes:

2401A00147 1AAAA
2401A00190 1BBBB
...
2713A00041 1BBBB
2718A00112 2CCCC
...
2745A00015 2CCCC
2810A00038 2CDCC
Here are the versions on my calculators:
2426A00270 1BBBB
2921A00174 2CDCC
2924A00028 2CDCC
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11-26-2019, 03:37 PM
Post: #22
RE: New-to-me HP-71B
My original 1BBBB was purchased in March of 1984, serial number 2422A00129.

https://www.hpmuseum.org/forum/thread-32...l#pid29765
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11-26-2019, 04:20 PM
Post: #23
RE: New-to-me HP-71B
(11-26-2019 03:37 PM)Dave Frederickson Wrote:  My original 1BBBB was purchased in March of 1984, serial number 2422A00129.

That's odd. Week 22 of 1984 is towards the end of May, or am I interpreting the serial number incorrectly?

There are only 10 types of people in this world. Those who understand binary and those who don't.
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11-26-2019, 09:21 PM
Post: #24
RE: New-to-me HP-71B
(11-26-2019 04:20 PM)grsbanks Wrote:  
(11-26-2019 03:37 PM)Dave Frederickson Wrote:  My original 1BBBB was purchased in March of 1984, serial number 2422A00129.

That's odd. Week 22 of 1984 is towards the end of May, or am I interpreting the serial number incorrectly?

From the Museum.

The correspondence of serial numbers to dates is only approximate.
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11-27-2019, 06:19 AM
Post: #25
RE: New-to-me HP-71B
(11-26-2019 09:21 PM)Dave Frederickson Wrote:  The correspondence of serial numbers to dates is only approximate.

Understood. From that page:

Quote:YYWW is not always exact and sometimes may have gone weeks or months without changing

That being the case, 2422 could be late May or any time thereafter until HP decided to change the week number again... Unless they preemptively started labelling calculators as from week 22, 1984 some time before that date.

There are only 10 types of people in this world. Those who understand binary and those who don't.
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11-29-2019, 06:33 PM (This post was last modified: 11-29-2019 06:34 PM by Dave Frederickson.)
Post: #26
RE: New-to-me HP-71B
(11-27-2019 06:19 AM)grsbanks Wrote:  That being the case, 2422 could be late May or any time thereafter until HP decided to change the week number again...

Note that my 71 was purchased in the 11th week of 1984 yet has a 2422 date code.

There is some speculation that the date codes relate to the fiscal calendar.

https://www.hpmuseum.org/cgi-sys/cgiwrap...read=55296
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11-30-2019, 03:17 AM
Post: #27
RE: New-to-me HP-71B
(11-29-2019 06:33 PM)Dave Frederickson Wrote:  There is some speculation that the date codes relate to the fiscal calendar.

A recent post in the HP facebook group by a former engineer in Corvallis said that in the earliest days, the date code specified a given h/w configuration, and that date code was used for all production up until the configuration was changed, then they switched to the new date and continued using that code, until the next change and so on, until at some point (probably as volume dramatically increased) they changed to the week of manufacture scheme, seemingly based on the week of the fiscal year.

This would explain why the earliest 35s (and 80's too I believe) all have one of only 2 or 3 date codes for all units.

It would be nice to have definitive answers on some of these obscure details.

--Bob Prosperi
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