MACINTOSH PLUS - possible to swap logic boards from different regions?


Macintosh Plus Logic boards. USA VS Australian

Hi all I have two Mac plus logic boards one is a US one from 1985 (120 VAC, 50-60hz 1 amp 60w)
and the other made in Singapore 1986 for Australian (200-240v 50-60hz 0.5 amp 60w)
Can I swap the USA logic board into my Australian Mac ?


Logically one would think it would be ok, as surely they would make the same logic board for all regions, and just make the power supply “different” for the different regions, but then changing the current to the “same” for the board…

But, logic is often a liar… so… I don’t know.

PS Used to know some Oois from Warracknabeal :slight_smile:


I believe the Analog Board (Power Supply) is different between regions, but the Logic Board is the same.

Occasionally there were region-specific releases of the Macintosh System Software, but any could be installed on any board, they weren’t specific to the hardware they were installed on.


Hi all,

Thanks for your help. Its very interesting to see the 1985 board, some components are mexican and phillipines made (never seen mexican made computer components before) and between the two boards - the resistors look about the same, capacitors I have no idea as the writing is too small.

I was about to swap them out tonight the CRT cut out. Turns out holding the analog board gets it back up but it remains black when I let it go. This happens now without fail 10 minutes after booting up from cold. Video here:

PS Us Oois have been around since the gold rush apparently, but Ooi is literally a “Smith” from where I come from :slight_smile:


Given my experience as an IT Technician, an old hat I don’t wear any more (there’s no money in building and fixing computers) I would say that a logic board is a logic board is a logic board. There is nothing on that board that is 110volt specific, so it should be a straight swap.

The difference between system software is that European iterations of the system software called the trash can a “waste basket” among the common annoyances of running system software from Europe, but in terms of functionality it should be much the same.

That type of thing generally happens when you have a crack in the circuit board. It’s not completing the circuit and so its failing. It can also happen if the plug connection is faulty. The first option there’s nothing you can do and generally you would replace the entire power supply unit, the later option you can resolder the plug back on properly and go from there.

I don’t generally open up PSUs as they contain capacitors that hold many thousands of volts and high amperage that if you touch will result in death. Broken power supplies are easily replaced, check eBay and the usual places. Much easier to replace a power supply than to replace your life.