Portable RAM Card 1MB -> 3MB by adding 658128ALFP chips. Is the B revision acceptable?

As we all know, the Macintosh Portable is most limited by the lack of RAM upgrades available today. If you only have a 1 MB card (or nothing at all), the computer can't effectively run System 7. While I wait for some genius's modern solution, I would like to try upgrading Apple's 1 MB card for the 5126 backlit model.

As you can see, this card was designed for a 1 MB or 3 MB configuration.



Theoretically, I can just add 16 more 658128ALFP chips (8 on each side). However, I am having difficulty locating these chips at a reasonable price. It seems like the B variety (658128BLFP) are readily available. These are fully static, rather than pseudo-static. Fortunately, the refresh pin is NC on the fully static B chip. Otherwise, the pinout and operation seems identical.

Has anyone had any experience upgrading these cards? Has anyone tried the B chips?

Thank you,

David

Garrett said:

When upgrading PowerBook 1xx RAM expansion cards, I've found that you can intermix PSRAM and SRAM on the same board. Everything just works. I don't know if that bit of info helps in your case, but it may be worth a shot just to try!

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Thank you. That's good to know. I've ordered some of the static RAM chips and I'll update this thread after trying them.