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Install Guide Part 6: Modifying a universal laptop power supply to work with the Mac mini

February 6, 2011

If you are using a pre-unibody Mac mini, the best way to power it in the vehicle is to modify a 120 W universal power supply capable of approximately 18.5 V output.

Parts & Materials:

  1. 120 W Universal DC-DC Power Supply
  2. Mac min Power Supply
  3. 2.2K-3.3K Ω Resistor
  4. Wire

Tools:

  1. Wire Cutter
  2. Wire Stripper
  3. Soldering Iron

Procedure:

  1. Cut the end off of the universal power supply and strip the insulation, exposing the power and ground leads
  2. Cut the Mac mini powers supply about 1/3 of the way from the connector and strip the insulation, exposing the power, ground, and iSense leads, be careful with the iSense wire as it is very small and easy to break
  3. Cut two short lengths of wire and strip the ends, solder these to the ground lead of the universal supply to create a Y
  4. Solder together the power leads from the mini cable and universal supply
  5. Solder together the ground lead from the mini cable with one branch of the ground Y on the universal supply
  6. Solder a resistor to iSense and the other branch of the ground Y
  7. Insulate all connections
    IMG_1078.jpg
  8. Use a zip tie to connect the two cables together and remove stress from the splice pointIMG_1080.jpg