Specialising

If you collect HP calculators actively, not be the sheer force of the fact that you buy a new one every so often, then you should think about the sort of collection you plan to build up. I have already written in an earlier article that trying to get one of everything is likely to be futile. I suggested that one alternative is to specialise. How could you do this?

One way is to choose a particular model and try to collect different types. For example the HP-35 had three different keyboards, it was made in the USA and in Singapore, and early models had just the words Hewlett Packard on the front whereas later ones had the model number too. Furthermore, early ones had several bugs, later ones had some of
these bugs removed, and still later ones had all the bugs removed. It could be very interesting to try getting several HP-35 calculators, showing all these varieties.

Another model that is interesting to specialise in is the HP-41. There are three basic versions - the HP-41C, HP-41CV and HP-41CX. Each can be found in the original style, and also in the "halfnut" style - with a rounded black mask around the display and with a much simpler internal layout. There are many different versions of the internal electronics and programs. There are models made in the USA and in Singapore. There is even the "blanknut" - an HP-41 with no function
names on the keyboard. Beyond all this, there is a range of accessories made by HP, such as plug-in modules, printers, card readers, most of which come in several versions themselves. Then there are the various manuals and solution books published by HP, and after that there is the enormous range of publications and accessories made by companies other than HP.

If you really want to study a model in detail you might find ways to get early prototypes, mock-ups, and production plans from HP. These are VERY difficult to get, but some items, such as detailed documentation, repair manuals, or diagnostic modules, were available from HP if you knew who to ask.

If you decide to specialise, do choose something which interests you, and something you can reasonably expect to collect. There is no point trying to collect many HP-35s if you live in a country where no-one ever used an HP-35, nor in trying to build up a comprehensive collection of HP-01 models if you are not willing to pay more than $5 each! Try to treat your collecting as fun!