HP 75C portable computer from 1982 runs FORTH and N-Queens

[@osiris1802]

I still own a fully functioning HP-71B with card reader, a IB connector and some modules (including the FORTH module) and I still love and use it. Machines from a time when HP used to make quality calculators and computers.

[@CalculatorClique]

The 71b looks great and has the HP keyboard we all know and love. I also like the 75C with the its bigger keyboard and display. Do you have any IB peripherals? I have the IB interface but no peripherals to test it unfortunately.

[@osiris1802]

@@CalculatorCliqueI used to own a HP plotter with IB interface (don't ask me for the model type, I forgot it, but I suppose it was a HP 7470A). But I don't have it anymore, unfortunately. I got rid of it as it stopped working and I had no opportunity (or rather nerve) to fix it myself and I only got limited space for my stuff to show. 🤨😩 Yeah, I know, that was stupid. The 71B is the star (or rather one of the stars) of my collection of HP calculators. There are also a 41C (also with card reader, thermo printer and some modules), 41CX, 34C, 21, 28C, 48GX and 42 amongst other (more modern) calculators from HP and other manufacturers like TI, Sharp and Casio. Last time I checked, they all worked flawlessly as far as I can tell. Yeah, I'm a bit of an HP calculator addict. 😉😂

[@CalculatorClique]

Nice collection 😊

[@LeicaM11]

I still also own an HP75C, but always lacked a handbook…

[@CalculatorClique]

I really like the 75C - I think it's underrated. They keyboard isn't a traditional HP calculator keyboard but it's large enough to almost touch type on. As it uses the same CPU as the HP 80 series desktop computers, software could be easily developed and cross compiled for it. Excellent scanned and and OCR'd manuals for most HP calculators and pocket computers are available at literature.hpcalc.org/.

[@hegedusuk]

I used to have the forth/assembler for my HP-71 -- and I even had the three volumes of the internal design and documentation, including full assembler details.

[@CalculatorClique]

The original FORTH module is hard to come by and expensive these days. A modern ROM emulator is available called the MultiMod if you want to be able to run FORTH and other ROMs again on your 71b.

[@rudiger86]

Nice video, my 75c has a sticky keyboard 😩

[@CalculatorClique]

Thanks for the feedback - much appreciated. I've recently spent a lot of time on the 75C and I really like it. The keyboard is not the traditional HP keyboard but I guess they were aiming for touch typing. I have a couple of keys that are a bit soft and don't click all the time but so far they still register every time. Have you checked the 75C Service Manual to see if the keyboard is easy to access to clean?

[@rudiger86]

@@CalculatorClique I did check the service manual and pulled the whole thing to pieces but unfortunately the keyboard is not removable, it’s actually plastic riveted in so the case would be destroyed if removal is attempted. I am using isopropyl alcohol and a toothbrush to try and clean in the keys and it seems to be working ok. DurryMuncha4Lyf!!