US 120V Macintosh Plus connected to UK 240V supply (conversion possible?)

[Will Cheyney]

Looking for some advice from the Macintosh community collective mind.

Some one has kindly offered me a Macintosh Plus that is a US 120V spec. They recently got it out of storage and forgot to use a step down voltage converter when connecting it up. Unsurprisingly the machine no longer powers on.

Firstly, I haven’t attempted a repair like this before and was wondering what the extent of the component damage could potentially be.

And secondly, could the analog board be permanently converted to International spec (220-240V) to negate the use of a voltage converter in the future?

Thanks!

 

[Solvalou]

Does it not power on at all? I wonder if someone tried to plug it in directly to a 240v outlet.

Hopefully the worst that could happen is an internal fuse has blown, or maybe some  chunky easy to source mains input components. Could be slot worse though of the voltage managed to travel further.

As for converting to 240v, chances are the only way would be to swap out the analogue board to that of a 240v model. Certainly that would be the easiest way. If you did that, it should be a straight swap I'd imagine.

I don't know if the circuitry on the 120v board may be different as it's obviously doesn't have to handle the voltage 'grunt'. If it is the same, then it may be possible to convert by cahnging some input voltage components, but don't take my word on that!

 

[Will Cheyney]

@tokyoracer I should have mentioned, I live in the U.K. so that’s why something blew on the board when it was plugged directly into our mains 240V supply. As far as I know, it doesn’t boot any more when using the correct 240 to 120 step down converter.

I haven’t been able to examine it for myself yet but wanted to get a head start on searching for a replacement if needs be. This led me to the idea of whether it’s possible to convert from one voltage spec to another - even if it meant replacing a few components on the board.

 

[bibilit]

Tokyoracer is right here.

The US AB cannot be converted to 240 V whatsoever.

Only the International board is able to do so.

Unfortunately, i think you fried the US board, i don't think the fuse was able to protect the components in time, so you best solution is to find a spare board or a complete non working Plus with a good AB board (a 128 or 512 will work also, but probably not the cheaper solution)