Casio FX-880P Personal Computer Teardown | Hacker News Reader

Casio FX-880P Personal Computer Teardown

neil.computer

81 pointsneilpanchal19 comments

I started looking around for other cool models. First I found this beauty, the fx-890p, programmable not just in BASIC but also in C (interpreted) and assembler:

https://www.thimet.de/CalcCollection/Calculators/Casio-fx-89...

And then there is this pocket Lisp machine:

https://casio.ledudu.com/images/pockets/casio/machines/zoom/...

There are a couple of emulators out there, this one supports the AI-1000 Lisp version too:

http://www.pisi.com.pl/piotr433/pb2000ee.htm

I have a pair of Atari Portfolios' in my retro collection, one of which is my original from the release, and the other was a contribution - and they're simply delightful little machines.

My original still has Turbo C on it, and all the programs I wrote during flights all over the place back in the 90's, keeping myself awake in obscure airports.

Very fun to dig it out, put in fresh batteries, and go back to where I was editing, ~30 years ago .. ;)

My GPD Pocket is still a better dev machine in that regard, though..

(I also have an Olivetti M10, which is like a Tandy Model 100 .. another delightful machine with saved state that goes back decades, instantly available with the insertion of a couple of ol' trusty AA's ..)

I think I first saw one of these devices in our house when I was a kid in the mid 80s.

My dad was (still is) an electronics engineer, and started a company making data logging devices for weather and environmental data, and was using these for data download and display.

His own computer was a self-built machine with a Motorola 6809 processor, with all the boards/parts mounted into an old Hoover Keymatic washing machine chassis [1].

It was funny for ~8yo me to learn that this tiny pocket-sized Casio thing and the Hoover monstrosity in the garage were both "computers".

Fond memories.

[1] https://www.ssplprints.com/image/83554/hoover-keymatic-washi...

> If somone designed a calculator today, they would most likely be made from ABS plastic, in a clamshell case.

Not so-- calculators are now such a niche market that it again makes sense to build for quality. You're not going to get any of the price shopper to begin with.

https://www.swissmicros.com/dm42.php

Absolutely so. There were at least a dozen plastic calculators available to buy at the office supply store when I was last there earlier this year.

Loved my Casio.

Back in the late 80', throughout the 90's, the Casio FX models were the high school and university beloved models.

With 850 and 880 being the wished for models of engineering university students.

Our education system did not had any kind of monopoly agreement like TI seems to have in US.

So I hardly can relate to the usual TI stories, it was all about Casio and some lucky ones got HP-48 variants.

> If somone designed a calculator today, they would most likely be made from ABS plastic, in a clamshell case. An ARM microcontroller that replaces essentially 70% of the chips, and it would be impossible to repair.

Interestingly, my Casio fx-115ES PLUS (which I love, BTW) uses a obscure but cute little architecture called nX-U8/100. Although I am a bit sad that it's hidden by epoxy like most cheaper calculators :(

I don't agree with the author here. The ARM replacing the chips is not bad, just the nature of what technical possibilities we have now. And having some funky chips in an old design does not help with repairing it.

I think OP has some sort of nostalgia that is not always well placed for old electronics.

OP here, I didn't phrase that right. It was meant along the lines of "Look at all these mechanical linkages, its all replaced by relay logic now-a-days". Indeed, a SoC + PMIC and a few stray bypass caps will replace the whole motherboard - that's a great thing.

It's sort of like appreciating old timers for doing what they had to do with the tools they had at the time - how NES game developers had 40KB of space to fit their game in which lead to some incredible resourceful hacks [1]. Obviously, today's game engines are "better" in every metric possible if by "better" we measure those metrics as higher/faster/easier == better. There is also a fascinating reason why a game engine like Pico8 [2] exists when we have almost unlimited compute/storage resources and if everything was "better" in the modern age :)

OP does have nostalgia, otherwise why would he purchase old useless gadgets? ;)

[1] https://news.ycombinator.com/item?id=21213840 [2] https://www.lexaloffle.com/pico-8.php

I can happily say your right but also just a little wrong in the best possible way. These guys https://www.numworks.com are building a “modern” graphing calculator, using an ARM Cortex-M chip and ABS plastic... but it’s an open hardware and software design that is documented and tinkering friendly.

I haven’t needed to buy one yet since the second hand CFX-9850GB PLUS i own is still working well enough for me, having picked it up out of nostalgia for having used that model through high school and university, but if that ever breaks I’ll buy one, I may even buy it before hand just to support their excellent work and commitment to open hardware.

It’s not open source. It’s “visible source”. CC NC license which is basically asking the community to do free work with nothing in return.

I believe that Radio Shack marketed and sold these as the TRS-80 Pocket Computer. I was probably in my 20's then.

https://en.wikipedia.org/wiki/Tandy_Pocket_Computer

“Although named after the TRS-80 line of computers, they were not compatible with it and didn't use the Z-80 CPU. Computers in the line were actually rebadged Sharp and Casio devices with different model names.”

The Casio FX-880P uses a Hitachi HD62002A01 CPU, which is a Z80 with a built in MMU. I suspect the "didn't use the Z-80 CPU" part may not be right for the Casio OEM'ed ones.

I have one of these, but the LCD is bad (terribly faint).

How would I go about fixing it?

Here is a video about replacing the screen. Also see video description for where a screen can (could?) be bought. https://www.youtube.com/watch?v=Oa630UVaWp0 Edit: Seems to be for a different version

The most likely culprit for display issues on these old calculators in my experience is the ribbon cables. You can take a multimeter and check the resistance of each connection, if any of them read too high you can solder a thin wire in parallel with it.

Or it could be the contrast potentiometer giving too high of a resistance, you can try cleaning the internal contacts or replacing it.

It only uses those two cell batteries? Wonder what it can do.

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