Has anyone made a reproduction RAM upgrade card for the Mac Portable? I’m cu how much of an undertaking that would be. It has a 90° connector but I think it’s something somewhat standard. Is there anything else unique about it compared to other Mac RAM modules?
Reproduction RAM cards for Mac Portable
- Thread starter Elemenoh
- Start date
8mb Memory Upgrade for Macintosh Portable M5120 & M5126
A MacEffects exclusive, a 8mb memory card for the Macintosh Portable series. The design was originally engineered by Techknight in 2014. Design updated in 2020, our 8mb upgrade card for the Macintosh portable uses the memory slot rather than the PDS. This card features red activity LEDs for...
maceffects.com
That?
It's funny you mention it. Stephen and I were talking about the possibility of making a new Macintosh Portable ram card. The Macintosh Portable doesn't use DRAM like most computers it using SRAM for the M5120 or PSRAM for the M5126. The connector is not a problem. It's sourcing the ram chips. It's on my todo list as well.
TechKnight's design uses SRAM for both models.
If you feel strongly about using PSRAM on the M5126, I have 310 Hitachi HM658512ALFP-8 512K X 8 PSRAM sitting here....This should be a good replacement for the Toshiba part, but pricey these days:
https://www.digikey.com/en/products/detail/cypress-semiconductor-corp/CY62167G-45ZXI/9771526
You, uh... collect SRAM or something?TechKnight's design uses SRAM for both models.
This should be a good replacement for the Toshiba part, but pricey these days:
https://www.digikey.com/en/products/detail/cypress-semiconductor-corp/CY62167G-45ZXI/9771526
There was a time when surplus chips from end of production runs or closed factories or whatever would show up on Ebay and sellers were just happy to have a market. There wasn't a system of folks determining the top price they could get.
During that time I stocked up on a number of things as they became available. Some, I'll likely never use, but others were pretty sweet. I had 250 of the TC55VBM4164, e.g., and supplied TechKnight with the chips he used for his hand-made run of Portable memory boards.
I got this one lot of memory that included the aforementioned PSRAM, 324 1M X 4 - 60ns DRAM, 249 2M X 8 - 60n DRAM, and 457 32K X 8 - 20n SRAM.
The 1M X 4 are good for populating Wombat boards, I guess. I haven't found a use for the others. The 32K X 8 SRAM would be great for caches if they were a little faster. 20ns is just a little slow.... They'd probably be useful if I was running off ethernet cards or SCSI cards and needed a small amount of local memory.
The problem with 2M X 8 chips is if you make SIMMs/DIMMs out of them, they're pretty low capacity. 2MB 30 pin. 8MB 72 pin SIMMs. 16 MB 168 pin DIMMs. I guess with double banks you can get the latter two to 16MB and 32MB respectively.
I also picked up a brick of 660 NCR 53C96 SCSI chips. If they were the 53CF96 that would be a lot more useful. Still, if the SCSI chip in a pre-AV Quadra ever goes out, I'm set.
The Cypress part for the Portable SRAM I linked above -- it looks like Mouser sells the same part and if you order 1000 of them the price comes down under $13 each, which is a lot better than $17, but still kind of pricey.
If the cards actually sell for $200, spending $42 on the SRAM might not be that bad. The other component probably don't add another $10, except maybe the circuit board.
Yeah trying to avoid having cards priced at $200. My goal would be to make at least a 3MB card for the M5120 so Mac OS 7.5.x can be used.
I got a 1MB Apple card and a 3MB Technology Works Super Static 3 card.
The plan was to use the design of the Super Static 3 to make a new design.
I got a 1MB Apple card and a 3MB Technology Works Super Static 3 card.
The plan was to use the design of the Super Static 3 to make a new design.
the version MacEffects sells is my design that I had licensed to him to do so.
Was there ever any progress on new cards? MacEffects are out of stock and no response as to whether they are doing any more.. I have a Portable en-route, and I just learned from @alxlab 's photos above that it has the Technology Works card in it. w00t!
As an aside does anyone have any info on that card, as the single Google result for it points me to this thread..
As an aside does anyone have any info on that card, as the single Google result for it points me to this thread..
I have a RAM card project in progress, just need to get my debugging setup in shape first
Cool, I'd been wondering about raiding PSRAM from some of the cards I have for PowerBooks. Might 4-8MB worth of the chips harvested from a fairly low capacity 1400 card work? 5126 possible, 5120 not?
Luggable is at 4MB now, so haven't thought about it a lot. No 5126 in collection, sigh.
Luggable is at 4MB now, so haven't thought about it a lot. No 5126 in collection, sigh.
It wouldn't work since the ram from a PB 1400 uses DRAM. You would need either SRAM or PSRAM. On top of that you would need to design a new RAM expansion module for the Portable. For the Portable all the logic for RAM chip selection is on the memory expansion card itself so it's more complicated then just slapping SRAM chips on a PCB and hooking it up to the connector.
Someone just posted this on reddit : https://github.com/miejas/Macintosh-Portable-4-MB-Memory-Expansion
No working board made but it looks promising
No working board made but it looks promising
I think Maceffects quit selling that version because of 2 problems. One, you cannot get the CPLDs anymore. and thats the thing pinching BMOW and his decision to potentially discontinue the Floppy Emu.
and two, the RAM ICs probably ran out, which is sad :-(
I have a dynamic engineering RAM card schematic, board layout, and the PAL code all on hard-copy which I think i posted in the TinkerDifferent discord at one point.
I will likely release my design public domain here soon because, well sadly its obsolete at this point but the knowledge gained can be useful.
and two, the RAM ICs probably ran out, which is sad :-(
I have a dynamic engineering RAM card schematic, board layout, and the PAL code all on hard-copy which I think i posted in the TinkerDifferent discord at one point.
I will likely release my design public domain here soon because, well sadly its obsolete at this point but the knowledge gained can be useful.
Yeah hopefully we can figure it out. You were able to simplify the logic versus my design.