48G memory expansion, is it possible?

[spencer]

I have heard rumors that it is possible to "memory expand" the 48G from 32K user available memory to 128K. Anyone know how to do that?

[Randy Sloyer]

Yes. Instructions:

1. Open calculator.
   
2. Remove 32K ram.
   
3. Install 128K ram.
   
4. Close calculator.
   
5. Enjoy.

Edited: 6 Nov 2003, 8:34 p.m.

[Ed Look]

Actually, Randy can be contracted to do this service for you; you can check his website. The link is found in this Museum.

[Erik Ehrling (Sweden)]

I have used www.cynox.de for upgrading several of my HP48G/GX's and have always been satisfied with the result. (Once the keyboard overlay was not fitted perfectly after the upgrade but they fixed that for free and I only had to pay for the shipping costs one way).

They also have several interesting options for the HP48G, one being a 1.2MB module - which upgrades the HP48G to have as much memory as you would have in the HP48GX with both a 128K and a 1MB card installed - another option being a double speed module - which in reality gives about 50% increase in speed.

There are some drawbacks with the speed upgrade, e.g. the clock goes faster as well and batteries last shorter time, but all in all I find a 1.2MB + double speed upgrade worthwhile! (It should cost around 110 Euro + postage)

Best regards,
Erik Ehrling (Sweden)

[Paul Brogger]

I've done a couple. 128K is easy.

256K is doable, but the lazy way I did it (trying to solder-bridge the upper memory chip pins to those on the lower chip) didn't last long at all. If you do 256K, find some way to firmly connect the second memory chip's pins to those of the first.

I've heard of three methods of opening the calculator:

1. taking off the keyboard overlay to get at the tops of some internal "heat stakes" (plastic posts with melted, mushroomed ends that hold the front & back of the calculator together);

2. cutting the heat stakes from behind the IR lens and from within the battery compartment; and

3. somehow (?) just prying the thing apart.

I don't trust the first to leave the keyboard face fully intact, and can't believe the third leaves no marks on the case. (There are probably people who will dispute these assumptions.) The only one I've tried is the second, and there are several web sites with descriptions of how to do it. It does require that holes be cut into the back case, but in places that are usually hidden, so I think it is the best alternative.

[Erik Ehrling (Sweden)]

Quote:

---

I've heard of three methods of opening the calculator:

1. taking off the keyboard overlay to get at the tops of some internal "heat stakes" (plastic posts with melted, mushroomed ends that hold the front & back of the calculator together);

2. cutting the heat stakes from behind the IR lens and from within the battery compartment; and

3. somehow (?) just prying the thing apart

---

It appears to me that Cynox uses the first alternative. If you look carefully between the keyboard overlay and the edge at the top you can barely see the tops of two screws, which I assume replaces the removed "heat stakes"

Best regards,
Erik Ehrling (Sweden)

PS. By the way, does anyone know where you can get a HP48*SX* upgraded to double speed? (There are descriptions of it on the net, so it can be done...)