What happen if USB Wall charger is plugged into laptop USB port?

[Peroxyde]

Hi,

I use a standard USB extender to power the fan of my laptop cooler pad. Today, my daughter borrowed my cooler pad. Unfortunately she has hookup whateever looks like USB plugs into her laptop:
1- The male USB plug which extends from the wall charger
2- USB wired mouse
3- Webcam Microsoft Lifecam Q2F

Then some weird things seem to happen. The mouse stops working and the webcam doesn't work. The non working mouse didn't bother, she used the trackpad instead. She let that run for a while until she really needs the webcam and asked why it doesn't work. Then I realized she hooked the USB charger into the computer. Unplugging this USB power cable + reboot the computer. The USB mouse can work again but the webcam no longer work. Windows 7 recognizes a generic USB 2Mpix webcam but no name and the webcam's blue light doesn't blink as before. Video test complain cannot connect to webcam. Tested webcam on 2 others computers and confirmed that webcam no longer work.

Question: what is the effect of plugging in an USB wall charger into the laptop USB port? Could that be the cause that toasted the webcam?

 

[T_Yamamoto]

Could be just coincidence?

 

[corkyg]

The wall charger provides a 5 VDC OUTPUT to feed devices. The USB port on a laptop provides a 5 vdc OUTPUT fo support devices. What happens is you have two outputs colliding, and laptop USB ports are not designed to receive voltage, but to dispense it.

I would say that could cause damage to the laptop's USB controller, and the webcam could be a victim. Seems to me that the USB wall charger should only have a female USB connector. But, yes, it could be a coincidence, or, more likely, collateral damage. Replace the webcam and record a lesson learned.

 

[TheStu]

The wall charger provides a 5 VDC OUTPUT to feed devices. The USB port on a laptop provides a 5 vdc OUTPUT fo support devices. What happens is you have two outputs colliding, and laptop USB ports are not designed to receive voltage, but to dispense it.

I would say that could cause damage to the laptop's USB controller, and the webcam could be a victim. Seems to me that the USB wall charger should only have a female USB connector. But, yes, it could be a coincidence, or, more likely, collateral damage. Replace the webcam and record a lesson learned.

Maybe it is one of those devices that has a standard USB A connector on both sides? I never did understand why those existed for this very reason.

 

[piasabird]

Sounds like you just ruined a laptop or at least all the USB ports and maybe you fed all the devices plugged in too much juice. You could try plugging in those devices to another computer to see if they will work. It might be just the USB ports that are damaged. If they are all integrated, then nothing much you can do. Hope you have a service contract or a warranty on the laptop.

 

[Peroxyde]

Thank you gentlemen for your opinion. It seems that the webcam is the only casualty. The laptop seems to continue to work OK. The USB controler in the laptop seems to be working OK too. Tested OK using another USB wireless mouse and another webcam.

To prevent the same thing from happening again. I glue all the USB cables in their socket. Now I realize the danger of an USB extender cable with two identical plugs.

 

[Vinwiesel]

Now I realize the danger of an USB extender cable with two identical plugs.

That sounds like a dangerous cable to have around. I fried a TV input once using a sketchy adapter that shouldn't exist.