Sunday, August 30, 2015

Modding an Apple Mac Pro Power Supply

 I got an old Mac Pro power supply to replace my puny old Dell.  The thing is massive!  79A of 12V power, that's over 900 watts!!

But, there's a catch.  Like all things Apple, it's a beautifully crafted, high quality unit.  And unlike the rats-nest wiring associated with PC power supplies, it's got a single clean wiring harness which is sadly undocumented on the Internet.
 I guessed the large connectors would be for 12V and ground.  Measuring the voltages would indicate the polarity.  BUT  How to turn the unit on?  I was looking for the equivalent of the PC's Green PWR Wire, the one that if shorted out turns on the power supply.

Going strictly by guess, I started shorting out pairs of connections.  I figured it couldn't do much harm, since none of the wires would be carrying current if the PWR wire were not engaged.
Using a paper clip, I quickly found the pair of PWR,GND connection.  I'm not sure which one is which, but for my purposes it doesn't really matter.  I made a note of the connections so that I'll be able to recreate them when I cons up a connector to the charger.

The outside big connectors are both GND, and the inside big connectors are both +12.2V.  The PWR/GND pair is the outside small connectors, second from the bottom.  The connector is oriented so the left side is smooth, and the right side has the edge.
A slight bit of fiddling showed that the small curve of a paper clip was the perfect size to connect PWR/GND.  I snapped a picture of it and will cover it with tape to ensure it stays put.

That's it for the experiment phase.  I'll use the flat blades from an old extension cord to bodge up a connector for 4mm bullets which is what my power supply uses.  I'll update when I do that!

Note: I think it's this model:  Apple 661-5011 980 WATTS POWER SUPPLY


Here's a video walkthrough:



blogodex = {"toc" : "Power Supplies", "idx" : ["Mac", "charging", "power", "electronics"]};

6 comments:

  1. I was looking for the equivalent of the PC's Green PWR Wire, the one that if shorted out turns on the power supply.DOE 6

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  2. hi did you test all other pin-out of the connectors ? can you draw a schema with tensions please???? thank you very much

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    1. Hi Mark Harrison, can you please test all the inside (Smaller) pins? This information would be most invaluable to the community. Thank you

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  3. Hi, nice job! that conector is the same of delta psu, i have a question, pin out is the same? i cannot found any information abou it on the web, i try this configuration in two psu from mac pro with delta psu but no sucess, thanks for any information.

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  4. Hi Mark Harrison, can you please test all the inside (Smaller) pins? This information would be most invaluable to the community. Thank you

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  5. Thanks so much for this information. I have to let you know I concur on several of the points you make here and others may require some further review, but I can see your viewpoint. dell power supply

    ReplyDelete