Underpowered (damaged?) USB port 2012 MBP

[pianoman88]

I purchased a refurbished 2012 MBP from Apple a few months ago. I attached am Epson scanner to it a few days ago and attempted to scan a document. The scanner would begin to move and then freeze; the software wasn't responding. I checked the software: I had the latest versions installed. After several failed attempts I began looking for a replacement scanner.

I decided to try one more thing: attach it to my 2010 macPro. It worked fine.

Is this a symptom of an underpowered USB port or ???

 

[Kissmyne]

No, it doesn't sound like an underpowered USB port, unless for some reason the scanner is designed to be powered by the port instead of a power adapter leading to AC Current(which would be ridiculous for a manufacturer to do)

Unplug the printer/scanner from the troubled Mac

Reset your printing system. https://support.apple.com/en-us/HT201539

Then reinstall the OS X driver for your printer.. most epson items are plug in and OS X will manage driver install.

 

[windywalks]

Try following the advice here:

http://www.macworld.com/article/2881177/how-to-reset-your-macs-nvram-pram-and-smc.html

It might help with problems with USB ports on your mac, I've had them acting up after plugging in and unplugging various USB devices - not recognising, not delivering a full amperage etc.

Worth a try and won't hurt your machine for sure.

 

[MagicBoy]

Not an underpowered USB port. In fact Apple can supply over double the current via USB to their own devices on request.

Most scanners require external power, I've only ever seen the odd sheetfed scanner and some LIDE Canons that didn't.