Introducing myself... and a question on a weird 48G


Hello all,
This is my first post after many years of lurking here... I just registered yesterday (it's been quite hard for me to find an email provider that was accepted by the system!).
I live in Italy, and of course I have a passion for HP calculators (and some other brands too, but mostly HP). My first HP was a 48G that I bought new in college... It's still working, even though it's REALLY battered - it has seen a LOT of use, and I had to open it many years ago, before I even knew what Internet was, so I had no instructions, and pretty much destroyed the face plate.

Anyway, in the years I built up a small collection (nothing comparable to the pro's!) but a few weeks ago, thieves broke into my office and opened the cabinet where I kept most of my collection (the wife doesn't understand the need to keep "old junk" at home...) so I lost almost everything. They only left a 41CV, maybe because it looked too old to be of value? And they left a 48gii, which is the one I loved (and used) the least. There were also a 12C and my original 48G safe at home.

Anyway, I've started buying some calcs to replace the ones I used most... mainly of the 48 series. And I bought a really nice 48G. It came from England, but I think it's originally from Germany because the manual is in German. It's made in Indonesia, and I was disappointed to find that it has painted keys (I thought all 48's had molded keys). And the font in the logo on the top right of the face plate, is a little different from all the other 48's I've seen. Anyway, it works, great, and it has the "blue on green" display that I love for sentimental reasons.

Now the weird thing... On the box (it came fully boxed) there is a very "official-looking" 512KB sticker; and indeed, the calculator has 512KB of RAM, one in each port from 0 to 3.
The calculator shows absolutely no sign of opening; the face plate is like new, and there are no cuts where the rivets are.
I don't think it was an "after-sale" mod, because in that case there would be no sticker on the box. I think it was sold already upgraded. But I've never heard of a 48G being sold that way, and my searches yelded no result. Does anybody know anything about this? Who upgraded it, and where (and for how long) was this setup sold?

Thank you in advance,


Hello and welcome:-)

There were some retailers in Germany (and maybe in other countries, too) who upgraded HP-48G (and other variants of the HP-48) units.

I had an 48G with 2.3MB RAM, and I still have an 48G+ with 1.2MB RAM.
On neither unit were visible opening marks.

There ways to open the HP-48 without visible destruction. The articles section of MoHPC should contain some info about this.



BTW: Since you use an upgraded 48G, I'd like to suggest to try SpeedUI, the real software turbo for the HP-48G series.


Hi Cristian!
Germany was the home of speedups and internal memory upgrades for the 48 series, dynatech sold them for years.
I, for one, have a 1280KB HP48G with double speed upgrade. No external sign shows that it was ever opened.

Welcome and greetings from Milan,


Here's one method of opening the HP48 without leaving much of a trace behind:

This is not the only way to do it. You could also open it via the faceplate and just stick on a new faceplate afterward. There are members here who have created various backplates on the 12C (?) so it's not too hard to imagine them entering via the faceplate and then affixing a new one later on.


Thank you for the replies and for the welcome! :)
I didn't know about the method that Han posted... I only knew how to open it from the back (cutting through plastic behind the battery door and the IR screen). I opened several 48s that way before, and they all look OK from the outside, but show obvious opening signs if you look behind those doors. They all also feel a little more "squeaky" when twisted, while this 512K specimen is rock-hard.
The faceplate of this modified 48, as I said, is perfect but has some almost unnoticeable differences; first, the "G" in the 48G logo top right, is a different font; then, it all looks a little "shinier", and it looks like it lacks the protective transparent layer that my other 48s have. I don't know if all Indonesian 48s look like that or if it really was opened from the front, and the faceplate was replaced.
Anyway... I wonder how many such modifications were made, and how many still exist! And also, I wonder how professionally the job was done - i.e. will it last, or not? :)

Does a 48G with 512KB eat substantially more batteries than a regular one?

I also read somewhere that a 48 with more memory is supposed to be slower than a regular one, due to bank switching; but after some tests, I can say that the 512K one is about 5-10% faster than a 32K one. Did they modify something else, or is it due to individual tolerances in the quartz frequencies?

I'm going to try the SpeedUI... Does it erase the memory or can I keep what I already have in there?

I also have a question on a 12C but I'll write another post for that!

Thanks again,


The speed increase for your memory enhanced 48G may be due to the garbage collection which occurs less often then on a memory constraint system.


SpeedUI is non-destructive, of course;-)

However you'll need to free enough memory in port 0 or 1 to store the main components CF.LIB, UI.LIB, and my special UFL.LIB level F which contains all 4 SpeedUI fonts.



Cristian; Welcome. Sorry to hear you were ripped off. May the thieves get what i think they deserve. The saddest thing is that the worthless sons-of-bitches probably threw them away when they found they couldn't change the TV channel with them.

Re: the 512KB sticker. That, and the responses were interesting.
Anyway - i put an "Intel Inside" sticker on the back of my 41cx. That really messes with the people who notice.


I know what you mean... We have an idea who might be the thieves (we can't prove anything of course) and they're definitely not the type interested in HP calculators (or math) at all. They probably took all my stuff to some flea market, to cash it quickly, where it will sit until someone buys them for a few Euros and then tosses them when they can't find the = key. That's what makes me saddest - old, rare calculators going like that.

The sticker... it's not on the calculator! It's on the box. The calculator itself looks like a perfectly normal 48G, if you don't check the internal memory.
And there was a receipt inside the "messages booklet", written in German, but I can tell it refers to the memory upgrade. It seems to refer to a "Cynox" brand...


There were several such companies. Cynox also made RAM cards as well as upgraded calculators.


where it will sit until someone buys them for a few Euros and then tosses them when they can't find the = key

Or reports here their fabulous flea market find!

Do you have serial numbers?

A question: what would be the "right" thing to do if you made a fabulous flea market purchase, and then were informed that you had somebody's hot calcuator (due to a serial number match, say)?


I would want to get the calculator, or calculators, back to the rightful owner. I would just feel bad keeping items that really belonged to someone else. If was a great flea market type purchase then I wouldn't be out much money either, so no big loss.

I say watch ebay and craigslist for your calculators. They may show up.


I agree, I would want to give them back. Or, being the original owner, I would be more than willing to pay back what the "new buyer" paid to get them, so that he doesn't loose the money (I would assume he bought in good faith).

Re. Serial numbers: I had them, but they all were on a spreadsheet file... which was on the laptop they stole. I also had a backup on an external hard drive... Guess who has that hard drive, too, now. :( Talk about putting all your eggs in one basket! But I was backing up for possible HD failures, not thefts! Now I have to find a way to backup "off-site" all my photos and other important documents at home, in case someone breaks in and steals my computer AND backups!!!

I will be monitoring eBay, but I really don't think they're the type of people who'd list stuff there. We think they were after the money in the office (there is money here, but they couldn't open the safe), and failing to get the money they blindly ransacked our cabinets.

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