Most of my collection has numbers below ¡°52,¡± so I agree the larger numbers are rare.?
Also note that all of my examples are 1969 ¡°models.¡± I wonder if HP went with your ¡°Possibility A¡± in order to keep the old serial number format for stuff started in 1969??
On Fri, Sep 2, 2022 at 5:06 AM Jim Adney <
jadney@...> wrote:
On Thu, Sep 1, 2022 at 10:07 PM, Jeremy Nichols wrote:
my HP-412A carries serial number 0978A19963. 78th week of 1969? A third example: the 3444A DC Multi-function plug-in for my 3440A DVM ?carries serial number 0973A07281. There must be some additional information we¡¯re missing. ?
Others have mentioned similar examples, and I have to admit that I don't know, but I can suggest two possibilities:
Possibility One: Some projects that HP started in a given year but ran into the next year, might have been given a year code in the year the project was started, or mostly associated with, in order to keep clear what year the project "belonged to." So the week designation would have been 52 + the following year's week. I would expect this to be a rather rare exception to the rule.
Possibility Two: HP wasn't really counting weeks, they were counting something smaller. Suppose you thought one day was too small an increment, plus it requires 3 digits to count up to 365. Dividing the year into weeks gives 52, which only takes 2 digits, but doesn't make good use of those 2 digits. Dividing the year into 5 day increments gets us up to 73 divisions per year, which makes good use of 2 digits but still leaves out both of your examples above. Dividing the year into 4 day increments gets us 91 divisions per day, which makes VERY good use of 2 digits. Since calendars that show the number of days from the start of the year were common back then, this might have seemed awkward, but it would have been easy to figure.
Personally, I lean toward Possibility One. Does anyone have examples of week codes above 78 or above 91? The week code on each of my HP instruments is less than 52.?
Jeremy Nichols