IIfx | IINTX 64-pin SIMMs

[ArmorAlley]

I'm going through my stash and I'm coming across more stuff.

I bought 4x 64-pin SIMMs from a fellow in Germany who suspected that they were for a IIfx.

The NTX part of the label indicates that these are intended for the LaserWriter IINTX.

I'm guessing that the 70L part at the end of the second line indicates that it is 70ns RAM.

I haven't found much online about this particular RAM, or even about the differences between IIfx RAM and IINTX RAM. I seem to remember reading somewhere that IINTX SIMMS can't be used in a IIfx.

There is a link to a thread here from the user Tempest who reckoned that they were 4MB SIMMs:





On AppleFritter, here's mention of it in a post from 2004: https://www.applefritter.com/node/3712

My questions are:

 1. Does anyone have any concrete experience with IIfx & IINTX SIMMs?

 2. Do these SIMMs ring a bell with anyone?

 3. Is it safe for both the SIMMS and my IIfx to try them out?

The picture of 2 of them is below:

/monthly_2020_06/large.EA7FC40F-DBE9-45FB-8AE1-A6298007FE6F.jpeg.1ffd4392c16801e87fa457586701fab1.jpeg

 

[dan.dem]

Hopefully I don't annoy anybody since I can't answer directly to your questions. But I have worked with/on IIfxes in the early 1990s.

I always prefer original sources, which means Apple in this case. Apple's Memory Guide:

https://www.macintoshrepository.org/24780-apple-memory-guide

states (p. 12)

[SIZE=10pt]The Macintosh IIfx uses 64- pin SIMMs similar to those used in the LaserWriter IINTX. Do [/SIZE][SIZE=10pt]not [/SIZE][SIZE=10pt]use NTX SIMMs in the Macintosh IIfx as they are not the correct speed. [/SIZE]

The original Apple leaflet for the IIfx ( http://tech-insider.org/mac/research/acrobat/9003.pdf ) mentions that 80ns SIMMs are needed. In the 1990s I often found that the original memory speeds became difficult to obtain, but faster modules mostly proved to be backward compatible. So this may indicate that your modules, it they prove to be 70ns, may work. What concerns me is that they are copyrighted 1990, quite early, so not sure about the 70ns.

However there are no warnings that LaserWriter memory may destroy fx hardware, so it may be worth a try, given the modules look in good shape. But you may encounter the startup crash sound (a minor down chord) and a sad Mac, which does not mean your hardware is toast but the Mac cannot start. However there is always a risk with unknown hardware. So I do not want to make actual recomendations.

Remember using always 4 identical modules per bank, and start filling up the fx with the largest modules in bank A (the latter required on many Mac IIs but not specifically mentioned for the fx). Parity memory may also be a concern, but only some specific (rare) models are requiring it, other models may (or may not) just ignore the additional information (same module form factor).

 

 

[ArmorAlley]

Hopefully I don't annoy anybody since I can't answer directly to your questions. But I have worked with/on IIfxes in the early 1990s.

I always prefer original sources, which means Apple in this case. Apple's Memory Guide:

https://www.macintoshrepository.org/24780-apple-memory-guide

states (p. 12)



The original Apple leaflet for the IIfx ( http://tech-insider.org/mac/research/acrobat/9003.pdf ) mentions that 80ns SIMMs are needed. In the 1990s I often found that the original memory speeds became difficult to obtain, but faster modules mostly proved to be backward compatible. So this may indicate that your modules, it they prove to be 70ns, may work. What concerns me is that they are copyrighted 1990, quite early, so not sure about the 70ns.

However there are no warnings that LaserWriter memory may destroy fx hardware, so it may be worth a try, given the modules look in good shape. But you may encounter the startup crash sound (a minor down chord) and a sad Mac, which does not mean your hardware is toast but the Mac cannot start. However there is always a risk with unknown hardware. So I do not want to make actual recomendations.

Remember using always 4 identical modules per bank, and start filling up the fx with the largest modules in bank A (the latter required on many Mac IIs but not specifically mentioned for the fx). Parity memory may also be a concern, but only some specific (rare) models are requiring it, other models may (or may not) just ignore the additional information (same module form factor).

This does sound good. I'll give it a go tonight, if I can.

Thanks.

 

[olePigeon]

Fast Page DRAM, 1MX1, 70ns, according to the Googles.

 

[ArmorAlley]

I can now confirm that they will boot up a IIfx on their own and that they are 1MB SIMMs.

 

[Unknown_K]

The original printer RAM was 100ns and was too slow for IIfx use. 

 

[maceffects]

As an incidental side note, I have seen others create 64pin SIMMs for Amiga but clearly say not for Macintosh use.  Does anyone know why exactly?  I can't be too hard to build new memory, at least I wouldn't think so.  I mean it would be nice to have 16mb modules for the IIfx.  If anyone knows more about this, please post. 

 

[ArmorAlley]

...but clearly say not for Macintosh use...

Stay away Mac-Folk, there is nothing for you to see here?

 

[maceffects]

Stay away Mac-Folk, there is nothing for you to see here?

https://www.ebay.com/itm/Amiga-GVP-RAM-SIMM-4MB-64-pin-module-NEW/193229327739?hash=item2cfd5d8d7b:g:2LwAAOSwvvJd3Yyg

They even stamped it on the PCB :lol:

 

[dzog]

They even stamped it on the PCB :lol:

Hah - along with 'Keep Retrocomputing Affordable', which I am loving. 

Maybe they're just nobly trying to prevent Johnny G et al from buying them all up and re-selling for massive markup. 

 

[maceffects]

Hah - along with 'Keep Retrocomputing Affordable', which I am loving. 

Maybe they're just nobly trying to prevent Johnny G et al from buying them all up and re-selling for massive markup. 

I thought maybe it was something along the lines of keeping the parts in the Amiga community.  I did see someone a year or two ago with 16mb modules and I asked him if they will work for Macs and that guy said no as well.  I can't fathom that if the speed and nature of the chips is correct why it wouldn't work. 

 

[Bolle]

The GVP pinouts are completely different so that’s why those SIMMs won’t work in the Mac.

It would have been quite a coincidence if two separate companies build non-standard RAM and have the pinouts match in the end

 

[dan.dem]

It would have been quite a coincidence if two separate companies build non-standard RAM and have the pinouts match in the end

Is Mac IIfx and LaserWriter RAM proprietary indeed? Not some sort of relatively uncommon but still standard RAM?

Does anybody have knowledge about this?

Early PowerBooks do suffer from this proprietory RAM issue, or more exactly their users were/are suffering. In the late 1990s I payed about 400 US$ for a 48 MB RAM card for my PB5300, and this was considered a bargain. Few month later I was able to aquire 64 MB of FPM for my 6100 for about 80$.

 

[Unknown_K]

Apple, GVP, and AST all use proprietary 64 pin SIMMs.

 

[dan.dem]

 

[dzog]

Welp, that explains that. It's a good warning to have on the PCB!

 

[maceffects]

Welp, that explains that. It's a good warning to have on the PCB!

Agreed!  If anyone finds an Apple 64pin 16mb or even 8mb, let me know. I’d be happy to have these reverse-engineered. 

 

[jeremywork]

Doug Brown already covered the PCB design, but IIRC the bottleneck to continued production has been finding available memory packages to install. They can be pulled from more common SIMMs of the period, too.

 

[joethezombie]

Yup, I have sourced a fair amount of NOS compatible memory chips and have several PCBs and a stencil ready for a few baking sessions.  I don't like the idea of destroying DEC memory modules, so sourcing unused specimens is difficult.

I've gotten most of my Mac stuff out of storage, and should have a quite a few of these to offer soon, many thanks to Doug Brown.