Model A1312 / Mid 2011 / 2.7 & 3.1 GHz Core i5 or 3.4 GHz Core i7 Processor, ID iMac12,2

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Fried 2 USB port- what to replace on the Logic Board?

Today I did something very stupid - I attached a USB 2.0 Hub to my iMac 27" and instead of powering it with a 5V power supply, I used a 12V power supply by mistake. Result: 2 of the 3 devices that were attached to the USB-Hub have been killed (a mouse & a Mac aluminium keyboard, my HTC One luckily survived).

Furthermore, and this is the worst part, 2 of my iMac's 4 USB ports don't work anymore!

I wanted to ask if there's any professional out here who know what exactly fried on the Logic Board. If it's just some resistor(s) or rather ICs, and which ones specifically can be assumed to have made it to silicon nirvana...

If it's clear what needs to be replaced I might find somebody with the necessary skills to accomplish the task. I've got soldering skills, but obviously for this job, you need a lab with SMD-soldering capabilities etc..

Update (11/01/2015)

I just bought a USB hub, and it works on 1 of the 2 fried USB ports. So 1 port is definitely gone. I assume it's not worth the hassle to try to fix the logic board as it might go wrong and cost lots of $$$. I advise anybody to look twice what power supply he's using before connecting it to a USB hub...

Answered! View the answer I have this problem too

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1 Answer

Chosen Solution

Most likely you blew the ports fuse links. These are small SMT devices on the main logic board.

But wait! I think you can live with this. You should be able to plug in a self powered USB hub on these ports and still use your system and devices. You see the fuse links protect your system from exactly what happened here on the USB ports power lines. The USB circuits are likely fine here as you stated the other ports are AOK.

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I will buy a new USB hub ASAP and get back to you. Thanks for answering so fast!


To gain a port, you can also go with a wireless keyboard and mouse.


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user100299334 will be eternally grateful.
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