A couple of (easy) questions about HP35

[Didier Lachieze]

Hi Ignacio,

I was hoping to see some experts popping up with clear answers to your questions….

In the mean time here are some fact about the different versions of the HP-35 (I recommend this article: Remembering The HP-35A, it is packed with details I’ve not seen elsewhere, such as HP internal memos).

1] the "5" key bump: according to the HP memo page 23 of the article above, it was decided with the introduction of the HP-80 in January 1973 to remove the bump, so all units built in the USA until the existing stock of keys with bump was used have the bump. Which means according to my observations: all 1143A, 1230A and almost all 1249A have the bump, late 1249A, 1302A and higher don’t have it. For the units built in Singapore the production of the HP-35 started in the second half of 1972 (exact date??) to address international markets outside of the USA and I don’t now if they started with the new keys or with the ones with the bump and then transitioned to the new ones.

2] the famous 2.02 bug: according to the second HP memo page 24 of the article above: all units built with a prefix starting with 1302A and higher are bug free, units with a lower prefix seems to have the bug if they were not returned for repair. Again no word about units built in Singapore. But your unit may have been returned and fixed.

3] front label: the “Hewlett-Packard” front label was replaced by “Hewlett-Packard 35” after the introduction of the HP-80, so all 1143A, 1230A, 1249A and early 1302A have the “Hewlett-Packard” front label. So it’s normal if your 1143S has it also.

Btw, it seems you have got one of the very early HP-35 built in Singapore. Would you mind posting some pictures showing details of the front, back and battery compartment?