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An eBay auction currently running (221041569757) features a PPC ROM that (allegedly) is marked with the same serial number as my PPC ROM. I asked the seller if he was certain about the number, thinking that, if he'd made a typo, he'd want to correct it before the item sold.... to head of the possibility of a Not As Described case. No answer. OK. Maybe I was too vague. I contacted seller again and said that his s/n was identical to mine. No response.

I have no problem with the guy ignoring me; it's his reputation* on the line, not mine. But I wonder if non-unique s/n - among PPC ROMs or any other HP-41-related hardware is a known thing.

*One member here wrote some strong words about this seller in another thread.

Each original order for the PPC ROM get two ROMs. I think they had the same number.

That would make a matched pair somewhat collectable.

Sorry to disappoint you, but the number is _not_ a real serial number, only kinda batch number.

The four numbers (2333) only indicate the production year and week, the 33rd week in 1983 in this case.



My recollection is that the original ones did have a stamped serial number, but it was with larger characters than the HP production week.

Certainly there will be *many* units that match the production week.

I hope Richard Nelson is reading these threads, because he can tell you everything you want to know about the PPC ROM's production.


Hi all,

Was more than one batch of PPC modules manufactured?

I mean, PPC module was a 1981 release, so, a 2333 s/n should belong to a later production run. All the PPC ROM's I've seen so far are 21xx (2146 - 47 IICR).

Obviously if some user got his PPC ROM housing damaged he may well place its internals into a nother case, replace the labels and super-glue it again... ;-)

Just some thoughts


I think there was at least one later batch. It seems likely that the PPC serial numbers were only put on the initial batch.

Another current PPC ROM auction 190693962335. This one arguably matches your description, Eric. Has 214?, in small digits, melted into the shell directly below "ID10/20 Singapore" and "2024A" in quite large type melted into the opposite side of the shell. My "2333" ROM has nothing at all on that side.

I always though that the large engraving was the Owner's PPC member#, and thus noting to do with the serial number...

I think I read this was done for just a few of the initial batch ROMs. Truth, legend, myth or else I cannot tell.

I think there was at least one later batch. It seems likely that the PPC serial numbers were only put on the initial batch.

I believe that there may have been two additional batches, but I don't think those had the engraving on the side. The original set of 2500 orders (each with two ROMs) had engraving with an "A" on one and a "B" on the other following the number. This was a sequence number from 1 to 2500 and a chart in the PPC ROM manual, starting on page 135 showed which members (by member number only) ordered which ones. For instance, my order was 78 and I kept "78A" while selling "78B" to another local PPC member in our Philadelphia-area PPC chapter in 1981.