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Atari Portfolio internal RAM upgrade?

R

Retroplayer

Experienced Member
Joined
Jun 6, 2023
Messages
172
I added an Atari Portfolio to my collection. I love the form factor, but of course it is by far inferior in specs to my HP200LX.

I have a couple of parallel port interfaces on their way. Looking at the asking prices of the serial interface, I will likely just spin my own.

One Parallel Port to keep as-is and the other to experiment with expansions.

Ordered a 1MB afpram drive for it as well.

The Atari portfolio came with only 128K of RAM of which 32K is the default RAM disk. Honestly, in most cases this is perfectly fine as the screen is only 8x40 text (240x64) and it is not 100% IBM PC compatible.

Unfortunately, as far as I can tell, the heydey of user interest has now faded and many of the old websites are gone. I haven't been able to find any information on internal RAM upgrades, but I do keep seeing references to them.

Does anyone here know anything about them? Maybe some old websites for me to visit via wayback machine? I think I can probably figure it out, but tried-and-true is always better than risking my one unit.
 
Just to add this here since I could not find this information anywhere when I searched for it.

The power adapter input is 3.0x1.1mm 6V center positive.
 
I did see that and the pictures should generally help.

It looks like the 4 lines from the DIP chip are CRA1-CRA4. CRA2-4 are not connected normally. This makes some sense (4 banks of 128K)

It is also picking up OA15 and OA16 off the memory card connector.

It is mentioned that all of the RAM was removed and replaced with the single chip, so likely decoding CRA1-CRA4 into A15-A18.

The fet and resistors appear to be replacing the Battery detect (BDECT) and probably CRA1-CRA4 are OR'd to generate the chip select. Replacing this circuit below:

1760045221693.png

1760045323682.png
 
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My order for the afpRAM card was cancelled. It was coming from the EU and apparently they are not shipping to the US right now. This will prioritize some other mass storage solution.

The largest original cards I can find are 128K and the asking prices are $60+ Not to mention that I would have no way of loading the files onto the card anyway from a PC. Well, not entirely true. I can do parallel port transfers to the Portfolio and save to the cards that way. A bit cumbersome, but doable.

A zip drive is an option, but it is bulky. I have some parallel port hard drives coming but no idea if those will work with the portfolio (the drivers may be too big even if it could work)

I guess I can see why the Portfolio didn't catch on! The HP 200LX doesn't have all of these insane hurdles to simply using it.
 
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