Oldest HP 41c aka earliest Serial Number


The museum database indicates 1926A....

Richard Nelson has an older one. PPC CJ V10N3P36 top right. His machine's serial number is / was 1916A00078. Time to update the list. :-)

How many machines earlier than 1933A are out there? I have two. Anyone else?



1933A02074 and 1953A12342.

The first one is a CL but not to worry, the original board is safely stored.


Edited: 2 Sept 2013, 1:03 p.m.





the best i can do is only a tall keys 2040A....

if this had been poker i could have tried a bluff


2005A here... also a tall keys, with a greenish display (which seems to be suffering the passing of time more).


1932A00186, purchased 8/2/1979. Original 41C, but replaced RAMs with 41CV parts making it a 41CV but with all original 41C firmware bugs (fun for synthetics).


Jim, I am jealous !

Not only are the 41cs old, that we have; the sad part is we bought them new!

My serial number would be -0349G00002 in the Hp scheme for dating

(Edited for German version)


For those of you who do not know.

Take the first two digits and add 60 for the year of issue. The second two digits for the week of production. The serial number at the end would mean second unit produced at the Quickfall family (one older sister).

What's your serial number everyone?

Edited: 5 Sept 2013, 3:35 a.m. after one or more responses were posted


What's your serial number everyone?

If I understand your sign convention, I'm -1407A00001

(that 7 might be an 8 - I don't have a 1946 calendar lying around!!)


For what it's worth, I've read that the year and week digits in old HP serial numbers are referenced to the HP *fiscal* year, and not the actual *calendar* year. I've also read that the week indicator did not necessarily increment on a weekly basis, but only after a production batch was complete.

Unfortunately, I don't have a large enough collection of HP calculators to evaluate either claim on the basis of empirical data....


Actually, an earlier post in this thread backs up the first claim (or, at least, the use of a different reference than the actual calendar year): Jim Horn posted that he bought serial number 1932Axxxxx on 8/2/79. Regardless of how you count, week 32 of the year cannot begin any earlier than day 218 of the year -- which is August 6 in all non-leap-years.


Hi John,

There has always been a controversy about the actual interpretation of the numbering method.

I am using the interpretation of the numbers as demonstrated in the HP 97repair guide. I am not home now so I can't access the illustration found in the repair manual but will when I get home.

At the moment let us use the following description found here at the museum::

Serial number museum definition.

Scroll down to 'decoding serial numbers'.

And here:

Another site.

Which may be a repeat. The citation aim, using as described earlier, is actually an HP document which says in effect the same as the above links.

Cheers, Geoff

Ah! found it from a previous posting as found in the HP 97 repair manual

Edited: 3 Sept 2013, 11:48 p.m. after one or more responses were posted


Wow -- definitive information from a primary source! Thanks for the picture and the links.


It is interesting to note the word 'week' appears to be a hand written correction. Not by me but actually part of the original document.


Geoff, for someone who I admire as a collector, restorer, teacher and pilot to say he is jealous of me... Wow.

I'm catching up on bills from seven weeks between jobs this summer. Rent, unfortunately, has precedence over HHC 2013. I *really* wish I could join you all there. But do have a great time - a wish I know will be filled and then some!


Will miss your input Jim, and well, I am flattered, to coin a phrase; "wow".






Can anybody be simpler?

i.e. 0001(letter)00001 (very early January 1960)



At least not a negative S/N :-)



[ "C" is for a "rare" Canadian made version :) ]


Mostly firstborns so far (or firt units produced at one's respective families, according to Geoff's convention). Does that mean subsequent units are closer to normalcy? :-)


Not necessarily -0349C00004 I am by far the geekiest of the lot. Hey Geoff we are the same vintage. Edit to correct serial format.

Edited: 5 Sept 2013, 6:45 a.m. after one or more responses were posted


It's just that I've heard firstborns are special, whatever that might mean :-)

Anyway, the sample is too small. Perhaps people don't want to share their serial numbers or just don't want to compute it. If such is the case, the following 12C program might help. Just enter your birthday date either in DD.MMYYYY or MM.DDYYYY (according to your date format setting) and press R/S for the first part of your serial number. This works only for Y>=1960, however.

01   ENTER
03 EEX
04 2
05 *
06 g FRAC
07 STO 0
08 1
09 0
10 1
11 +
12 EEX
13 2
14 /
15 x<>y
16 g DeltaDYS
17 7
18 /
19 g INTG
20 1
21 +
22 RCL 0
23 EEX
24 4
25 *
26 1
27 9
28 6
29 0
30 -
31 EEX
32 2
33 *
34 +
35 GTO 00


Those of you who were born before 1960, use the following version and change the sign of the result.


22 0
23 RCL 0
24 EEX
25 4
26 *
27 1
28 9
29 6
30 0
31 -
32 x<=y
33 CHS
34 +
35 EEX
36 2
37 *
38 +
39 GTO 00

Edited: 4 Sept 2013, 8:02 p.m.


Neat program!

Hello everyone, those going to HHC should wear their production number!


Stick a zero in front of the 3 Paul!!!


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