Breaking the 36MB RAM limit on the LCIII

lilliputian

Tinkerer
Mar 6, 2022
231
96
28
Los Angeles, California, USA
That's a big'un!

Here's a photo of mine that holds them at a slant. Now, these are 30-pin SIMMs, and so wouldn't be suitable for an LC III, but they also made ones for 72-pin SIMMs as well. (These particular ones are "SimmSaver/30" modules, loaded with four 256k SIMMs each.)
 

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lilliputian

Tinkerer
Mar 6, 2022
231
96
28
Los Angeles, California, USA
Btw, if you look for SimmSavers specifically, the nomenclature is a little confusing:

SimmSaver-30 Ad - MacWorld July 1995 pg 229.png



SimmSaver/30 - 4x30-to-30
SimmSaver/8 - 4x30-to-72
SimmSaver/8² - 8x30-to-72
SimmSaver/32 - 2x72-to-72
 
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Sphere478

New Tinkerer
Aug 22, 2023
15
0
1
Noticed something... maybe you all are already aware but the module I ordered isn't wired like a normal simm it seems the two sides of the simm contacts are separately wired.

was that anticipated?
 

Sphere478

New Tinkerer
Aug 22, 2023
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0
1
Glad I saw that before trying to plug it into something lol.

any insight?

if memory serves, there is also a 256mb version of this module which basically confirms that pinout is non standard at the very least, damagingly incompatible at worst. As 128mb is the max for 72-pin simms usually

asked the seller what they knew about them, this is what they said

“Hello, Those mem boards come from a HP HPUX Workstaion, models C100, C110, C160, C160L or a C180. Those workstations use PA-Risc processors. They are installed in pairs.”
 
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trag

Tinkerer
Oct 25, 2021
268
128
43
Glad I saw that before trying to plug it into something lol.

any insight?

if memory serves, there is also a 256mb version of this module which basically confirms that pinout is non standard at the very least, damagingly incompatible at worst. As 128mb is the max for 72-pin simms usually

asked the seller what they knew about them, this is what they said

“Hello, Those mem boards come from a HP HPUX Workstaion, models C100, C110, C160, C160L or a C180. Those workstations use PA-Risc processors. They are installed in pairs.”

In my experience, the PA-RISC work stations used standard 72 pin SIMMs. At least the ones I worked with did.

HP made a pretty penny claiming you needed their special memory in their PA workstations and in their printers of the time....

I once ordered a PaintJet XL300 (IIRC) and it would not work with the HP brand 72-pin memory installed. I installed some no-name 72-pin SIMMs I had on hand instead and it worked like a champ.
 

Sphere478

New Tinkerer
Aug 22, 2023
15
0
1
So there is no doubt that these are compatible with normal simm sockets?

why would they separate the pins unlike normal simms? What did the sockets that these went into look like? Any chance they have more pins on the underside?
 

trag

Tinkerer
Oct 25, 2021
268
128
43
So there is no doubt that these are compatible with normal simm sockets?

why would they separate the pins unlike normal simms? What did the sockets that these went into look like? Any chance they have more pins on the underside?
I wouldn't say that there is "no doubt". It's always possible that HP made more than one line/revision of PA RISC systems using different pinouts in the 72 pin sockets. That seems unlikely, but back in the day of mini-computers a lot of unlikely things happened...
 

Sphere478

New Tinkerer
Aug 22, 2023
15
0
1
Found a ebay listing with a interesting claim.

this is supposedly a lc-575 logic board in a color classic with the power pc upgrage

here is the interesting bit.

seller says that it is 132mb which is functional under the 6040 but only 36mb is functional under the power pc processor.
 

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