Vintage Palmtops Tips & Tricks


RAM expansion for Atari Portfolio

UPDATE [2020/04/12]:
By popular demand, I decided to take more detailed photos of the expansion board and post them here. The author is (apparently) unreachable, and I don't have any schematics or technical knowledge of the circuit, so please, don't ask me about it. I won't be able to help.

The original RAM (U5-U8) has been removed. The board is one-sided; the numbers on the two chips are as follows:

1113 618819


It's been a long time since I wrote here. SillyVenture 2k11 is over and I was there, but had no time to write even a short report. Today I promised myself to write a post, that has been waiting in a queue for long.

RAM expansion. The must-have mod if you want to use something else than the built-in software on your Portfolio.

Already in the 1989 128k was too little. With 4 kilobytes taken by display RAM, at least 8 KB used as ramdisk and some memory used by system (depending on FILES and BUFFERS settings in CONFIG.SYS), less than 100k was available for the program. With 40-kb ramdisk (absolute minimum when you wanted to upload some software) you were left with no more than 60 kilobytes. RAM expansions appeared soon after Portfolio, the first ones being large, uncomfortable interfaces mounted to the expansion bus. Early mods built in the Portfolio were two times the price of the computer. As years were passing by, more and more sophisticated solutions were emerging for affordable prices - both commercial and fan-made.

In the 2000s, with the twilight of Atari Portfolio, RAM expansions have become extremely hard - if not impossible - to acquire. This makes the computer virtually useless for any applications but using the built-in software, especially for coding. It was clear for Maestr0 - a talented constructor who decided to create a new 512 KB built-in RAM expansion for Atari Portfolio.

Apart from expanding my Pofo's RAM, Maestr0 replaced the capacitors, making my computer run 10 minutes without batteries!

Maestr0's construction includes a small PCB mounted on the Portfolio's mainboard. It's intended to be as cheap as possible and easy to assemble. When the author decides to release it, I'll inform you about pricing, shipping conditions and how to purchase.

Comments (28) Trackbacks (0)
  1. As the new owner of an atari portfolio I’d be very interested in a memory upgrade, any word on pricing / availability?

  2. Hi. I am interested in this mod. I could build one myself, but I would rather just buy one as it is a lot quicker. Please share a link, or email me any information you can. Thanks.

  3. I am interested in the details of your memory upgrade. Can you provide more info please?


  4. Hello! I am interested too! Great MOD! I was working on my own until I found this forum! Please email me with any information you can, I would like to buy, or build exactly the same mini board! 🙂
    Regards! Ondrej

  5. Hi,

    please send me any infos on that memory upgrade. Thanks!

  6. Also interested. Please send me info abt this.

  7. I’d love to know more about this mod. Please send me any info.


  8. Please, send me info about this upgrade of pofo.
    Thanks in advance !

  9. Hi, were can i get a Memory Expansion ?


  10. I am very interested in a memory upgrade, more info please.

  11. Hi there,

    is this upgrade still available? I am interested!

    Best regards,


  12. Is there any chance to get one?

  13. Any hope for getting any information about this mod / contact to Maestro?
    What caps did he replaced with what different caps?

  14. I would really like to get this ram expansion, can you please help me ?

  15. Do you think maestro will be willing to give us details on how to build this expansion? (Given that he is out of bussiness)

    Thanks in advance

  16. As like many others I am a fellow Portfolio enthusiast and would love to get more information on this upgrade. If you can, please email me with further informantion. Thank you

  17. Being a fairly recent owner of the portfolio I totally agree with you that RAM expansion is a must have Mod. I would be extremely grateful if you could provide any further info on this upgrade.

  18. Hi I have 2 atari Portfolios, and am interested in the memory upgrade, can you please send me some details.


  19. hello,

    i am also interested

  20. Hi

    I’d also be interested in the mod itself or a technical description of it (I could likely source the parts and perform the mod myself but it’s not clear in the picture what the six patch wires are for or what the replacement chip is)

  21. I’d like to buy one of these . Would you please email me?

  22. I’ve been coming back to this page for years, in hopes of some change. This board was made, so maybe the gerbers are out there? Is there a possibility of buying this thing? I’d love to have a buncha ram. 🙂

  23. Hi, would you be able to give me the email address of the board maker?

    Thank you.

  24. Interested in a quantity of the upgrades. Anyone found Maestr0

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