Introduction

This is a description of a successful reactivation of dead USB ports on the mentioned MacBook model. Do this with care and only if you know what you are doing! Do it on your own risk!

  • Both USB ports of a MacBook were dead after a shortage or overload on a Ramps Board that was connected to the Mac via an Arduino Board.

  • Normally Mac OS shows a message that tells you that the USB device got deactivated due to a power surge on that port. In this case the message wasn't displayed. It was later displayed after a reboot. Anyway both USB ports were instantly dead.

  • Here and there in the internet people advise to perform a SMC reset. That was done but didn't help. But you should try the SMC reset first.

  • Make yourself familiar with the pinout of your USB cable. Find the ground (GND) and measure with a multimeter if there is still an connection between both ground pins of the USB ports.

  • Check that there is really no power between ground and the +5V pin of the USB cable.

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  • Double check that you have a proper working, good quality desktop power supply. https://en.wikipedia.org/wiki/Power_supp...

  • Set it to +5V DC and double and triple check the power and the polarity with a multimeter.

  • Connect ground of the USB port with ground of the external desktop power supply.

  • Maybe you can use just a usb cable but I preferred to use a cable with a device. I used an FTDI breakout board from sparkfun because there the pins are relatively good accessible.

  • Supply the USB device (I suppose on the port that caused the problem) with 5V from the desktop power supply on the 5V pin of the USB plug.

  • The LEDs on the FTDI light up and it is recognized by the Mac.

  • For whatever reason the second USB port got reactivated, too. It works without the need to provide the connected USB device with external power.

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Finish Line

Axel

Member since: 04/18/2017

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