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Injecting current from an external PSU into a classic PS board

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  • 68kMLA Supporter

Hi all,


I have a faulty PSU in my mac classic, despite my attempts it still does not work

I noticed that the AC-DC is isolated from the DC-DC part in the board, so do the CRT board downward.

So, I have the crazy idea that by removing the transformer and the optoisolator, at this point I could inject the current from an external PSU into the pads where the voltages is supplied to the MB. Pls look at the picture.


This could give power to the CRT and the MB. The DC DC it still connected but it would not, in my opinion, create problems.

The question is: would I create smoke and burn the rest of my Classic or is there a change that this works?

As it is obvious I'm not an electronic engineer: please be kind to me :)





Yes, I know my PS board is really a mess, capacitor leaking has compromised it.

Do not worry if the regulator and the optoisolator are not in place in the picture, the restoration is still on going.



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