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!


Here's a video walkthrough:



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Tuesday, August 11, 2015

Concord Model Engineers, August 11, 2015

CONCORD MODEL ENGINEERS MONTHLY MEETING MINUTES

Tuesday, August 11, 2015

CALL TO ORDER:  7:30 pm
ATTENDEES: 16     GUESTS:  0

MEETINGS:

Monthly meeting, Second Tuesday, 7:30 at Concord Airport Terminal.

Friday Fun Fly, Third Friday, 7:00 - 9:00 pm.
Gym at the Church of the Nazarene, 1650 Ashbury Dr., Concord

Fun Fly this month on Friday, Aug 21, Tenative, awaiting confirmation.

TREASURER REPORT:

treasurer absent.

OLD BUSINESS:

none.

NEW BUSINESS:

A quiet meeting, hoping all absent members are enjoying their Summer Vacation!

We will continue Indoor Fun Fly.  Cost to club is now $50, we will ask each attendee
to contribute $5.

UPCOMING EVENTS:

Aug. 16, Masciano Control Line Contest. Alameda. Contact Jim Perrson.email,  james.persson@SBCGlobal.net

Aug. 21-23, Jim Perrson (and others) will be running Tether Cars at the Good Guys West Coast Nationals. http://www.rodauthority.com/event-coverage/car-shows/goodguys-27th-west-coast-nationals-pleasanton-ca/

Aug 29-30, SacRats.org

Aug 29-30, Control line speed contest, Napa.

Sept 5, Weigel Field, free flight contest.

Sept 13, Crows Landing, Former Naval Air Base, Flying Giants event, all day.

Sept. 26/27, Control Line Combat event at the Flying Electrons field. http://lferc.com/

EVENT REPORTS:

Oakland Cloud Dusters.  1/2 Coupe, rubber powered, Ding Zarate 1st place;
.020 Gas, Jim Muether 1st place; OCD Cat, Lynn 4th place; P30 (13 entries), Lynn, 3rd place
3 max (90 sec) + P38.

RAFFLE:

1 Gal Sig 10% Nitro, Sig 1/2A Dewey Bird, Horizon Lipo Cell Voltage Checker,
Husky Screwdriver set, BHM Little Ike.

MEETING ADJOURNED:  8:20


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