Think I fried my usb ports (question about working one)


macrumors newbie
Original poster
Jun 11, 2015
Ok, im stupid. I tried this trick:

Basically it's a trick that allows you to charge a phonebattery with an old usb cable and a computers usb port. You cut it, peel it and stick the black to negative and red to positive on the battery, plug the usb in and it will charge. Problem is, i accidentally did reverse (black on +, red on -) and the computer died.

When i rebooted it, my usb ports are not working properly anymore. One is completely dead, the other one port still kinda works, but everytime a plug a device in, a message pops up that "it's drawing to much power etc.." and it takes 4 - 5 seconds, then the usb device is recognized. After this the device seems to work fine. I tried resetting SMC and PRAM, no difference.

Why is the message popping up everytime and is there a way to get rid of it? Since it's an old mac can live for now with one usb port (will never try tricks like this again for sure....)

My computer is a mid 2010 white unibody macbook, and i bought it through a company that buys old/broken/second hand computers, repairs them and sells them refurbished with warranty. Is it worth contacting them about this?



macrumors 68000
Jan 29, 2008
Sounds like a hardware issue so there's little you can do but replace/repair it. I would send it in for warranty repairs if it's covered.


macrumors regular
May 25, 2004
USB controllers have over-current detection. Sounds like something is still shorting out internally from the damage, or the controller's current detection is broken. I've seen similar messages from a PS3 I bought used; the USB socket pins had become delaminated and shorted to themselves, so it was a very mechanical issue in that case- putting on a new USB socket fixed the issue. In this case it is likely purely electrical so probably not a lot that could be done without replacing the logic board, except maybe if someone desoldered the existing USB controller and put a new one on (no idea the feasibility of that for a Macbook though).


macrumors member
Jun 9, 2015
Bad ideas 101, cheap no name USB charger yes, Notebook computer :eek:

Yes that's so true. It's actually a very neat trick, mind you. Worth it to try. But bah gawd why would you try that on a notebook, let alone a Macbook with its low-to-none USB port replacability (I've no idea about other laptops but I assume it won't be much worse of that of a Macbook).

I'm sorry about your predicament now but I don't think there's anything you can do except bring it in to a service. It's going to be very expensive if it's the logic board, mind you, and it might be worth it just to cut your losses and get a new one.