Macintosh Portable Memory Expansion

[PacificState]

I have a Mac Portable M5120 with 2MB RAM, and I'm curious to know what options there are for RAM expansion at this point. MacEffects used to sell an 8MB card (which I believe Techknight designed?) which is now out of stock, but I also think there may have been schematics on this site before the crash. I'm OK soldering, but I also think the RAM chips may be in short supply(?) at this point. Any ideas?

 

[Berenod]

Indeed, the problem is finding any of the needed SRAM chips.
Pretty much not to be found anymore, which is why Mac effects can't offer their expansion cards anymore.
So even if your soldering skills are up to scratch, without the SRAM chips you won't be getting anywhere!

I too have a portable without the memory expansion, and with the 1meg onboard you're pretty much limited as what you can do with the machine...

Second hand cards do pop up every so often, but mostly in the US, I'm from Europe, which makes US based stuff just too expensive, with costly shipping and import duties added onto already relatively high asking prices...

 

[PacificState]

Thanks. What I hadn't understood is that while the Mac (it's a non-backlight M5120) comes with 2MB of memory, 1MB seems to be on the motherboard and (as you hint at) 1MB appears to be on a card I didn't realise was there ;-)

Does this mean the expansions differ between the backlight and non-backlight?

 

[Berenod]

Thanks. What I hadn't understood is that while the Mac (it's a non-backlight M5120) comes with 2MB of memory, 1MB seems to be on the motherboard and (as you hint at) 1MB appears to be on a card I didn't realise was there ;-)

Does this mean the expansions differ between the backlight and non-backlight?

Indeed, there actually is a difference between the non-backlight and the backlight versions.
The non backlight uses SRAM, the backlight version psram.
I know the Techknight/Mac effects card uses SRAM and works on both the backlight and non backlight portables, I think this compatibility is only one way, so psram will not work on the non backlight portable.

Might be wrong though!

4MB would already be good, allows you much more flexibility in which is to run, less then 4 and you're pretty much stuck with system 6.0.8...

 

[Trash80toHP_Mini]

ISTR linking to a DRAM expansion card that might be a great target for reproduction. I vaguely recollect that it was done by the Masters of Memory at Connectix?

edit: nope, hardware wizards at NewerTech

DRAM based Mac Portable Memory Card - Newer strikes again!

Completely missed this one. MacUser June 1990 if memory serves: @techknight If the board supports 8MB, does it stand to reason that they managed to hit the full 9MB point you managed to achieve on your card? Should have checked Newer's web site for info on this one, but no time ATM

68kmla.org

 

[techknight]

me and @androda are working on newer design which contains readily available chips, which unfortunately are BGA.

Good news is, its a single-chip RAM solution which simplifies the select/decode logic.

 

[Trash80toHP_Mini]

Very glad to hear that, best of luck. But, I was under the impression that BGA was developed to be easily implemented?

 

[nunes.hr]

Any updates?

 

[micheledipaola]

While we keep finger crossed for our Portable wizards @techknight and @androda developements, having a Maceffects 8mb card myself I can confirm it also works in a backlit BUT (as their website states very clearly) you need to set a jumper on the card to make it acknowledge the different model AND in this case you will only get +5mb.

 

[desertrout]

Keep an eye on this page: https://androda.work/product/macintosh-portable-7-megabyte-ram-card/
A first run was completed and have sold out, but parts for another much larger run have been received and are being assembled.

 

[micheledipaola]

totally Portable-noob question, related to the memory expansion: since it takes so long to wait until the RAM test on boot is completed, would not be possible to create something like a ROMinator for the Portable? would it even make sense? I mean, there is a ROM slot, and I am aware of ROM cards out there... but no idea about what they could do. Cut the RAM test? Maybe is it even possible to add more features?

 

[SuperSVGA]

totally Portable-noob question, related to the memory expansion: since it takes so long to wait until the RAM test on boot is completed, would not be possible to create something like a ROMinator for the Portable? would it even make sense? I mean, there is a ROM slot, and I am aware of ROM cards out there... but no idea about what they could do. Cut the RAM test? Maybe is it even possible to add more features?

You can override the built in ROM or expand on it, or even add a ROM disk. Though I believe disabling the built in ROM requires changing a jumper on the logic board.

 

[micheledipaola]

You can override the built in ROM or expand on it, or even add a ROM disk. Though I believe disabling the built in ROM requires changing a jumper on the logic board.

changing a jumper is what you do on other machines (Iici for instance) to switch to the romSimm, so nothing terrible. I am surely unable to do something like you are mentioning @SuperSVGA but did someone started some similar project? because I would say that would be an awesome one...

 

[SuperSVGA]

changing a jumper is what you do on other machines (Iici for instance) to switch to the romSimm, so nothing terrible. I am surely unable to do something like you are mentioning @SuperSVGA but did someone started some similar project? because I would say that would be an awesome one...

I've been thinking about designing one, like a diagnostic card to help with issues like a bad SWIM. Unfortunately I haven't found a bad SWIM to test with yet and haven't had enough money to order PCBs yet.

The difficulty does depend on what you want to do with the ROM code itself. Disabling simple things like the RAM test isn't too difficulty, but more advanced modifications would need some work.

 

[desertrout]

Unfortunately I haven't found a bad SWIM to test with yet

I have one somewhere on my bench if you want it.

 

[micheledipaola]

I've been thinking about designing one, like a diagnostic card to help with issues like a bad SWIM. Unfortunately I haven't found a bad SWIM to test with yet and haven't had enough money to order PCBs yet.

The difficulty does depend on what you want to do with the ROM code itself. Disabling simple things like the RAM test isn't too difficulty, but more advanced modifications would need some work.

If I should write a user's wish list, underlining the wish part and not knowing a thing about hardware limitations, I think it would be:

turning on/off RAM test
accessing advanced system diagnostics (checking batteries / psu too?)
getting a (customizable / nvram?) ROM disk / boot like in ROMinator II
...
...