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Released April 2010 / 2.4, 2.53 GHz Core i5 or 2.66 GHz Core i7 Processors

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One usb port works, second does not. This is the second unit like this

Hi guys,

This is the second unit I’ve rebuilt that has one good usb port, and one that has power only, no data. I tried SMC and NVRAM. Nothing seems to happen during the SMC reset. The power cable does not blink, or anything similar, as described in the process. Not sure what to do, aside from supplying a USB bank with the unit. Why would it supply power and not data? Nothing is recognized, from a mouse to a Flash Drive. But it will supply power to a usb light. Any ideas appreciated. I also tried just holding the power button down without any power connected. Currently, there is no battery in the unit.


Answer this question I have this problem too

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Clearly the logic board has damage, its either the USB connector contacts which are damaged, the traces & components to the internal USB hub logic from the port and then onwards to the PCH.

You really need both the schematics and board-views for your logic board to trace out and test the voltages as well as the signals.

You’ll need the skills to read them and how to use the tools to diagnose as well as repair your board, and lastly access to the parts!

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Thanks, Dan. I was afraid of that…

I saw a YouTube video, guy made it look easy. It was a J4906 or something, cap that was missing or went bad. That’s why it’s good to have spare logic boards.

Am I doing the SMC right? Why doesn’t the light blink on the power cord, or anything indicate that I’ve reset it?


Resetting SMC won't help you here, you do appear to have done it.


Thanks again, Dan. Guess I need to learn how to do this. It's seemingly a common problem. Have you seen it before?


Sadly, yes! A common cause is a power surge either because the devices power unit was not the right one (24v unit plugged in a 12V unit was needed) or a power surge or lightning strike snuck in via the unprotected power brick. Damaged port contacts is also an issue.


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Thom Hemler will be eternally grateful.
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