HP48s/g with expanded memory

[Marco Polo]

I am looking for a 48s/g with memory expanded internally (48s at maximum possible, 48g about 1mb).
On TAS i have found a bunch of 48g, but nothing about what i am looking for.
Is there any source for such calculators?
What could be a fair price?

TIA

[Hiwi]

Hi,
from time to time you can find one on ebay, but often they are from an estate of a deceased
and the sellers do not know anything about ports or pinit...

There is no company anymore which does a conversion or upgrade so far as i know.

But you can do it yourself, it is not a rocket sience.
An upgrade is very simple up to 768k. you need only 2 or 3 SRAMS and a flipflop and some wiring.
Many are afraid of opening the HP48, yes that's the most important thing.
But you can do it without leaving any traces...

Ralf

[Maximilian Hohmann]

Hello!

(04-13-2023 02:48 PM)Hiwi Wrote:  But you can do it yourself, it is not a rocket sience. An upgrade is very simple ...

"Very simple" must have a very individual meaning, because the author of this document, in which he describes the process of expaning the RAM of an HP-48G, writes about it "Warning: It's a hard work..": http://www.datacomm.ch/grundsch/page_upgrade.html

The problem with finding an HP-48S/G with a RAM extension is that people who did it themselves don't part with their calculators. And if someone else sells it for them (because they can not protest any more) he or she will probably not know that the calculator has been modified...
Why not just get one of the "X" models and put a RAM card in?

Regards
Max

[Marco Polo]

(04-13-2023 04:58 PM)Maximilian Hohmann Wrote:  Why not just get one of the "X" models and put a RAM card in?

Good question.
And, unfortunately, i have also a good answer.
As a matter of fact i own both a 48sx (with 128kb card and equation library. It was my calc at the university) and a 48gx (with 128kb and 1mb Cynox cards).
The gx is almost mint.
In my company many engineers use HP calcs, most of them 48 in all different flavors.
We found that the 48 are prone to "change owner without being sold or gifted" and many colleagues lost their calculator.
I use a 50g (and have a spare one) for daily job and, for some reason, is ignored by such gentlemen.
I would like to use my gx, but I am afraid of loosing it and the cards inside.
A beaten 48s/g with hidden expansion would easily be ignored....

[Hiwi]

Hi,
let me quote the author of the article:

Quote:Upgrade
32k to 128k (easy)
128k to 256k (more difficult)

It is not a very sophisticated task and why not ask anyone with skills in the forum?
I did the upgrade many times for me and collegues.

You can get G with keyboard problems for less than 30 Euros, and fixing the keyboard will always result in an ram upgrade :-)

Anyway my intention to upgrade were the 'collectors' prices of the ram cards. 1MB for more than 250 Euros here in Germany, ouch. The diy 768 K upgrade was only 10 Euros for parts and one hour 'hard' work :-)
I have a GX as well and bought a 4MB card on ebay. But it turns out, that it was not fully working.
I have some sparcom cards and could transfer the libs to my G model.

[Siegfried]

Mark Fleming used to sell newly made RAM cards for around 40 Euros and published the documentation.

[mfleming]

(04-16-2023 07:26 PM)Siegfried Wrote:  Mark Fleming used to sell newly made RAM cards for around 40 Euros and published the documentation.

I'm on hpcalc.org! Sweet!

Send the Gerbers to your favorite PCB house and hand solder your own RAM cards. No need to open the 48 case, which is quite the pain, believe me...

https://github.com/mafleming/HP48RamCard