Reproduction RAM cards for Mac Portable

[pocketscience]

Hey @techknight - I picked up one of your cards second hand. It kinda works, but sometimes I get a Memory Manager Error and need to reboot. If I select "About Finder" it does this for example. But I tried a few other apps and games and they worked fine. It's not clear how the jumpers should be configured, including the additional blue jumper cable that came with it... I couldn't find any doco anywhere, so hoping you can assist.

Cheers,

 

[techknight]

Basic system software doesnt support that amount of RAM or it will crash. This is normal.

You have to have a full install, for the portable install in order for the system software to not crash on About this Macintosh.

Also, the wire is there to connect to the ROM slot /AS when using it on a Backlit portable or it will not see all 8MB of RAM. Also the 7MB cap jumper is there to cap the RAM to a max of 7MB so the backlit portable will work properly. the backlight control occupies the 9th MB of space on the M5126.

 

[pocketscience]

OK, thanks. I've got a M5120 so I can forget the wire. Sounds like I can leave the jumpers as they are also and just use the Portable system install and it should be golden..

 

[MICHAENTOSH]

@techknight I bought the 8MB MacEffects card for use with my 5126 but it didn't include the jumper cable or documentation. Can you please tell me where the cable attaches to the RAM Card and then where it attaches to the motherboard? Do you still have any I can get? Do you still have any cards I can get?

 

[techknight]

@techknight I bought the 8MB MacEffects card for use with my 5126 but it didn't include the jumper cable or documentation. Can you please tell me where the cable attaches to the RAM Card and then where it attaches to the motherboard? Do you still have any I can get? Do you still have any cards I can get?

Unfortunately the cards are long since EOL, you cannot get the RAM chips anymore, and perhaps even worse, the XC95 series of CPLDs are now slotted for EOL.

It has been awhile, but i think the jumper wire goes over to the /AS signal on the ROM header. But dont quote me on that, since ive not used/made one of those cards in eons.

 

[Applemuseum]

I got that card from MacEffects at the time but it did not include instructions. Does anyone here have them Andi’s willing to post them? In those instructions should be the correct connection point for the cable documented.

MacEffects claims that they lost them and can’t help….

 

[trag]

Was the thread that covered their creation on 68Kmla.org lost? The details were covered extensively there. Techknight posted as he developed/troubleshot the cards.

Edit: Okay, this point in the 68KMLA thread seems to be where the wire starts getting discussed. I'd read the whole thread...

https://68kmla.org/bb/index.php?threads/designing-a-portable-ram-card.314/post-5868

Also, I'm pretty sure that these chips:

https://www.digikey.com/en/products/detail/alliance-memory-inc/AS6C1616-55TIN/4234581

could be used to make more of them. But the chip cost would be ~ $11 - $12 each, rather than the $2.50 Techknight had. I don't know about the CPLDs.

My only concern in substituting those chips is that they do not operate in 2M X 8 mode, only 1M X 16, but I think (but am not certain) that techknight used the original chips in 1M X 16 mode. It should be pretty clear by looking at his design and what he did with the pin that controls the chip mode.

 

[JDW]

I got that card from MacEffects at the time but it did not include instructions.

I have that card but didn't purchase it from MacEffects because it came inside a 5126 Portable I purchased.

@techknight is the engineering wizard who created the original design and licensed it to MacEffects:

https://tinkerdifferent.com/threads/reproduction-ram-cards-for-mac-portable.390/#post-3127

I show a photo of the connection point required to enable all the RAM here:
https://tinkerdifferent.com/threads/bluescsi-on-macintosh-portable.2764/page-8#post-28807

Take note of the processor slowdown when you enable that RAM, as I mention in this separate post here:
https://tinkerdifferent.com/threads/bluescsi-on-macintosh-portable.2764/page-8#post-29565

UPDATE!​

Found the printed documentation and uploaded it as a Resource here:

https://tinkerdifferent.com/resources/manual-for-maceffects-ram-card-for-mac-portable-m5120-m5126.144/