Luc Pauwels

The HP28 WWW Archive

What's New?

It finally happened: the dodgy battery cover on my HP28S broke. This is the very first problem I have had with my HP28S calculator in over 25 years! It doesn't look like there are any replacement battery covers available, but there are other clever solutions out there to fix this problem.

Well, It has been a long while since the last update, but now there is actually something new: I found an online copy of the HP28S manuals! Have a look at the Bibliography section for the download links.

Actually, everything and nothing. I used to maintain this archive when I was working at the University of Leuven as a scientific researcher, almost 20 years ago. When I left the university, the archive stayed online for a few more years until it finally shut its doors.

But now it's back. I haven't changed anything to the contents (yet), you should keep in mind that the HP28 was a very advanced calculator in the late 80's, but nowadays is more like a curiosity. Nevertheless, I still have my original HP28S (purchased in 1989) and it continues to work beautifully.

So for every HP28 enthousiast out there, and there may still be some left (I hope), the archive is here again! If you are still using an HP28S, or if you are the author of any of the programs listed here, please send me a message. It's always fun to find out what happened to you during the past 10 years ;-) Enjoy!


Welcome to the only WWW site dedicated to the Hewlett-Packard's HP28 calculator family! The initial model (28C) was first introduced on January 5th, 1987. One year later, it was replaced by model 28S which was sold from January 4th, 1988 till April 1st, 1992.

For the moment, this archive contains mainly postings I dug up from the HP28 archives back in '90 and '91. The information in the Hardware section applies mainly to the HP28S, but most things in the Programs section should work fine on the HP28C as well, unless stated otherwise.

If you would like to have your own submissions added to the archive, mail them to Luc.Pauwels AT and I'll add them as soon as possible. Pointers to other HP28 related stuff on the Web are welcome too! Please note that I am no longer working for the Centre for Computational Linguistics. However, they graciously allowed me to keep maintaining my webpages. Nevertheless, it may take some time before your submissions get added.

The HP28 WWW Archive is not affiliated with the Hewlett-Packard Company.

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