Can externally powered USB hubs damaged a switched-off MB?


Short question: Can a powered USB hub, connected with an unoffical 5V adapter damage an Asus P5K motherboard that is switched off?

long explaination.
I have (had) a P5K Asus motherboard which I bought second hand. It worked fine for the first couple of days after purchase and I believe that there was no defects with it.
Shortly after I bought it, I needed to connect a USB webcam to it. I had a USB hub which I connected it to. This usb hub was unpowered and I needed some extra juice to power the camera. The USB hub has a 5V DC adapter hole for extra power. I had such a plug adapter from PCMIA USB card that I use with my laptop to allow me to connect USB-powered external hard drives. I have used it many times on my other desktop via a PCI USB card (the motherboard USB ports were 1.1).

I connected the hub directly to my new computer via the motherboard and presto, the camera worked and I used it for a few hours on Skype. I shutdown the computer, waited a few minutes and then disconnected my externally powered USB hub. I had noticed that there was still power going to the now-switched off desktop as the cd drive lights and HDD lights were flashing. This didn't strike me as unusual as on my older computer, the motherboard light would light up when I connected the USB hub to it.

The next day when I switched on my computer the video card was malfunctioning and would not display a picture on screen. I heard the characteristic long beep and three short beeps from the BIOS which indicates a video card problem. Replacement video cards have not worked which makes me feel it is the motherboard that is faulty. I think it does load to Windows logon screen so there is may not be damage to the harddrives or processors. I have ruled out memory issues as well as each module works in another desktop. The graphics card I am not so sure. This motherboard has no native VGA port, only PCI-E graphics card ports.

I have exhausted every solution I know for getting the graphics to work and just ordered a new MB. I just need to know or maybe warn people about this.

Has anyone ever damaged a motherboard in this way?
Is there any solution to this?

Lastly, does anybody wants a MB with a burnt out PCI-E graphics port? lol.
2 answers Last reply
More about externally powered hubs damaged switched
  1. It's POSSIBLE, but I'd say it's pretty unlikely at the same time. USB does carry a small amount of power, and so I suppose if you had a bad hub that was sending spikes of power down the connector cable, it could cause problems. The "unofficial" AC adapter doesn't really do you any favors either.
  2. Cl-scott

    You were right.. After ordering the replacement motherboard, the same problem still persisted. I checked the graphics card in another computer and discovered it was defective, probably as a result of the motherboard. I

    In conclusion..
    Don't connect powered USB hubs with unoffical AC 5V adapter to P5K motherboards.
Ask a new question

Read More

Asus USB Motherboards