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Is my 128K to 512K converted motherboard done by Apple?

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I have a Macintosh 128K (a European version, 220V) which is converted to a 512K. It looks like just te chipset has been upgraded, but is it done by Apple (see attached photo)?

The chips are branded with NEC so that makes me suspicious that it is not.


  • Is this an original Apple-factory upgrade from 128K to 512K or is it done by someone else?
  • Do you have any clue what the “Apple 16” sticker (round, white with red apple logo) on the large chip might mean (see photo)?


Best regards,



The Netherlands



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Usually a Factory Apple 512K upgrade required a swap of the logic board, not modifying the existing one. They also supplied new badges to replace the original ones.


Also, I've never seen an original Macintosh board with socketed memory (after the issues they had with the Apple ///)



It was very common (and relatively cheap) at that time to modify a 128k to accept more memory, I also have one of those modified board here for repair and I wrote how to undo the modification ad restore it to the original 128k here: https://68kmla.org/forums/index.php?/topic/26604-macintosh-128k-issues/?p=300816

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Ferrix is right. Apple only swaps out the board and badges.


Consider that at the time there were no authorized Apple Repair Centers, Apple Tech got their certification through correspondence courses and given access to ordering Apple Parts, many computer stores hired Apple Techs for Apple Repairs, and some were quite scrupulous in their practices.


Furthermore, when Larry Pina published his Mac Repair and Upgrade Secrets books, people began to do their own repairs and upgrades, including logic board swaps.


Given that, chances are sometime in its early past somebody swapped out the logic board from your 128 to a 512K or 512Ke board. If it does not have he official badges swapped or overlayed over the old ones, then chances are it was done by somebody outside of Apple.

Edited by Elfen
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Interesting. I can’t see it as the image will not expand for me when I double click it for some reason.


Long ago I seen/read an article on Byte Magazine on how to expand the 128K to 512K by piggy backing RAM chips onto the others on the board, and wiring up the board’s multiplexer chips to them for the proper addressing. Other magazines also published the same article with a BIG Warning “DOING THIS WILL VOID YOUR WARRANTEE!” I’ve also seen actual 128K boards modified up to 512K in this fashion back in the day, so I know this was possible.


I doubt Apple did this as Apple would just swap out the board. Chances are somebody got their hands on one of these upgrade articles and did it themselves. I’m just weary of such projects – I built my first CPU back in ’76 from a Popular Electronics Magazine article “Build Your Own CPU!” And there was a mistake in both the instructions and the schematics, so when I plugged it in *POOF!!!* “Where all this smoke came from?!!”  Popular Electronics wrote an “ERRATA” Article on “Build Your Own CPU” article the following month with corrections. But it was too late for this 13 year old... I spend too much money and time to get it together and get it going and lost it all when it went up in smoke. Too bad my grandmother threw out the board – an actual wooden block with the ICs tapped into it and wires everywhere!  If I knew then what I know now... I would have been a dangerous teenager.  :D

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