adding memory to an IBM PS/1 Model 2123

Hi there

I am trying to add memory to an IBM PS/1 Model 2123

The IBM PS/1 Model 2123 has 2 MB of non removable RAM and two
connectors for 72-pin SIMMs. From what I have found on the web, it can
handle SIMMs up to 8 MB each, giving a total of (2 * 8) + 2 = 18 MB of
RAM.

I have tried installing Hewlett-Packard 8 MB 72-pin SIMMs in the slots,
but they aren't recognized. When I turn the machine on, it counts
memory till " 02048 KB ". It seems it cannot see memory above 2 MB.

I have the Reference Diskette and I have started it and chosen
"Automatic Configuration" (or Automatische Konfiguration since it's in
German) but it does not help.

Is there something I am doing wrong ?
Do I need special SIMMs ?

Thank you,
Daniel

wrote in message
oups.com...
Hi there

I am trying to add memory to an IBM PS/1 Model 2123

The IBM PS/1 Model 2123 has 2 MB of non removable RAM and two
connectors for 72-pin SIMMs. From what I have found on the web, it can
handle SIMMs up to 8 MB each, giving a total of (2 * 8) + 2 = 18 MB of
RAM.

I have tried installing Hewlett-Packard 8 MB 72-pin SIMMs in the slots,
but they aren't recognized. When I turn the machine on, it counts
memory till " 02048 KB ". It seems it cannot see memory above 2 MB.

I have the Reference Diskette and I have started it and chosen
"Automatic Configuration" (or Automatische Konfiguration since it's in
German) but it does not help.

Is there something I am doing wrong ?
Do I need special SIMMs ?

There is an "Advanced Diagnotics" disk image for the PS/1 2123 located at
http://www.ps-2.org/mirrors/ps2supersite/ under the heading "Miscellanous".

Ye gads... A PS/1. I was still firmly entrenched in camp Amiga for a few
more years after the PS/1 arrived on the scene. If I ever locate an english
version of the Reference Disk I'll email you. PS/2 ones are easy to find.
Not so with the PS/1, unfortunately.

Tony.

wrote in message
oups.com...
[...]
I have tried installing Hewlett-Packard 8 MB 72-pin SIMMs in the slots,
but they aren't recognized. When I turn the machine on, it counts
memory till " 02048 KB ". It seems it cannot see memory above 2 MB.

I have the Reference Diskette and I have started it and chosen
"Automatic Configuration" (or Automatische Konfiguration since it's in
German) but it does not help.

Is this Reference Disk also called the Starter Diskette? The image for the
model 2123 can be found he
http://ps2supersite.homedns.org/pccbbs/ps1/ (2123strt.exe).

Is there something I am doing wrong ?
Do I need special SIMMs ?

I see that there are 72-pin Fast Page Mode SIMMs, and EDO SIMMs with and
without parity. There are businesses that sell memory specific to the PS/1.
I'm am wondering if you got yours this way or maybe thought any 8MB 72-pin
SIMM would do.

Tony.

Thanks for your reaction.

I downloaded and wrote the image on a floppy. I booted on it. It is
similar to the "Reference Disk" I already have, although I understand
English much better than German

Anyway I installed my SIMMs, booted on the disk and chose "Change
Configuration". Alas, the "installed memory" field cannot be changed,
while other fields like the type of floppy disk can be changed...

So I'm stuck with the same problem: The PS/1 doesn't "see" the SIMMs I
have installed.

Here's more information on the SIMMs: There's a sticker on it with:
- the HP Logo
- 1818-6838
- 8 MD EDO 60 (2Mx32)
- Reorder D3647-63001

Searching the web for these reference numbers, I found these SIMMS have
the following characteristics:
- 8MB
- EDO
- 60 ns
- 72 pin

Okay, but now what kind of memory do I *need* for my PS/1 model 2123
?

Thank you,
Daniel

wrote in message
oups.com...
Thanks for your reaction.

I downloaded and wrote the image on a floppy. I booted on it. It is
similar to the "Reference Disk" I already have, although I understand
English much better than German

Anyway I installed my SIMMs, booted on the disk and chose "Change
Configuration". Alas, the "installed memory" field cannot be changed,
while other fields like the type of floppy disk can be changed...

So I'm stuck with the same problem: The PS/1 doesn't "see" the SIMMs I
have installed.

Here's more information on the SIMMs: There's a sticker on it with:
- the HP Logo
- 1818-6838
- 8 MD EDO 60 (2Mx32)
- Reorder D3647-63001

Searching the web for these reference numbers, I found these SIMMS have
the following characteristics:
- 8MB
- EDO
- 60 ns
- 72 pin

Okay, but now what kind of memory do I *need* for my PS/1 model 2123

8MB 72-pin, Fast Page Mode, SIMM modules with parity.

http://www.siliconmt.com/solution.html
http://www.memoryx.net/92g7203.html

EDO memory came out in 1995, long after the PS/1.

Tony.

On 28 Dec 2005 02:17:17 -0800, wrote:

Thanks for your reaction.

I downloaded and wrote the image on a floppy. I booted on it. It is
similar to the "Reference Disk" I already have, although I understand
English much better than German

Anyway I installed my SIMMs, booted on the disk and chose "Change
Configuration". Alas, the "installed memory" field cannot be changed,
while other fields like the type of floppy disk can be changed...

So I'm stuck with the same problem: The PS/1 doesn't "see" the SIMMs I
have installed.

Here's more information on the SIMMs: There's a sticker on it with:
- the HP Logo
- 1818-6838
- 8 MD EDO 60 (2Mx32)
- Reorder D3647-63001

Searching the web for these reference numbers, I found these SIMMS have
the following characteristics:
- 8MB
- EDO
- 60 ns
- 72 pin

Okay, but now what kind of memory do I *need* for my PS/1 model 2123
?

Thank you,
Daniel

Please pardon my curiosity, what is the reason you want to resurrect
this dinosaur that I thought was extinct long ago? Even with memory
upgrade, what it can be used for, except for a computing history
museum exhibit? Even high end P3 systems are getting junked these
days because their time has passed...
NNN

On 28 Dec 2005 02:17:17 -0800, put finger to
keyboard and composed:

Thanks for your reaction.

I downloaded and wrote the image on a floppy. I booted on it. It is
similar to the "Reference Disk" I already have, although I understand
English much better than German

Anyway I installed my SIMMs, booted on the disk and chose "Change
Configuration". Alas, the "installed memory" field cannot be changed,
while other fields like the type of floppy disk can be changed...

So I'm stuck with the same problem: The PS/1 doesn't "see" the SIMMs I
have installed.

Here's more information on the SIMMs: There's a sticker on it with:
- the HP Logo
- 1818-6838
- 8 MD EDO 60 (2Mx32)
- Reorder D3647-63001

Searching the web for these reference numbers, I found these SIMMS have
the following characteristics:
- 8MB
- EDO
- 60 ns
- 72 pin

Okay, but now what kind of memory do I *need* for my PS/1 model 2123
?

Thank you,
Daniel

AFAIK both IBM and HP fiddled with the Presence Detect pins on these
modules. If it is not an EDO issue, then it could be that the PS/1's
BIOS/chipset does not know how to correctly interpret the PD data, or
the PD pins may not be programmed. If it is a PD issue, then you could
possibly reconfigure the SIMMs by adding or removing links to/from
pins 67-70. For example, an 8MB 70ns IBM SIMM (p/n 92F0102) connects
pin 69 to ground and leaves the others open.

- Franc Zabkar
--
Please remove one 'i' from my address when replying by email.

wrote:

Please pardon my curiosity, what is the reason you want to resurrect
this dinosaur that I thought was extinct long ago? Even with memory
upgrade, what it can be used for, except for a computing history
museum exhibit? Even high end P3 systems are getting junked these
days because their time has passed...
NNN

It's indeed just for computer history. I collect various computers and
I had the chance (?) to find this PS/1. Now I intend to put Linux on
it, but it will never run with only 2 MB of RAM. So I'm looking forward
to add two 8 MB SIMMs to it.

Of course, the performance of this machine (386 SX at 20 MHz) is
ridiculous. And indeed, stuff like complete Pentium II or Pentium
III-class machines can be found for like 20 EUR.

Anyway SIMMs that will work on this PS/1 seem hard to find. I've
googled with "PS/1 Model 2123" and some sites sell such RAM, but 1)
it's expensive for old stuff and 2) it's not 100% sure they will work
on this machine...

Cheers,
Daniel

Sorry but I don't think I'm able to go solder the pins. That's pretty
difficult for me.

I see some people are selling "PS/2" memory on ebay. Does that mean
that kind of memory chip will work on my PS/2 2123 ?

Thank you,
Daniel

wrote:

It's indeed just for computer history. I collect various computers and
I had the chance (?) to find this PS/1. Now I intend to put Linux on
it, but it will never run with only 2 MB of RAM. So I'm looking forward
to add two 8 MB SIMMs to it.

DOS