Did I damage my mobo?

[lodingi]

Computer in my sig has been working flawlessly for more than 3 years. On a recent boot, I accidentally hit my wireless adaptor. This adaptor is plugged into a front usb port. The computer rebooted and once into windows, I lost use of my keyboard & mouse (both usb). Rebooting has no effect.

I opened the case & unplugged the front ports from the mobo. I then booted into windows, & still, no keyboard & mouse. I went to check the rear ports. When I would touch any of the usb cables, the computer again reboots.

I'm guessing I shorted out the usb ports on the mobo. I figured I'd check in with my fellow [H] before setting out to find a replacement board. I would appreciate your input. Thanks.

 

[/usr/sbin]

Check grounding in the case.

 

[lodingi]

Check grounding in the case.

I'm out of town until Friday, but I will when I return home. I'm curious what could have changed after 3 years of stable usage?

 

[SpunkySpine]

Computer in my sig has been working flawlessly for more than 3 years. On a recent boot, I accidentally hit my wireless adaptor. This adaptor is plugged into a front usb port. The computer rebooted and once into windows, I lost use of my keyboard & mouse (both usb). Rebooting has no effect.

I opened the case & unplugged the front ports from the mobo. I then booted into windows, & still, no keyboard & mouse. I went to check the rear ports. When I would touch any of the usb cables, the computer again reboots.

I'm guessing I shorted out the usb ports on the mobo. I figured I'd check in with my fellow [H] before setting out to find a replacement board. I would appreciate your input. Thanks.

The USB jacks on the MB all have a metalic sheild that goes all the way around the connection for the nine pins for signal and +5Volts. It's designed to provide sheilding to prevent electrical noise to other devices, whether they be onboard the computer or any other device such as a nearby radio receiver or TV set. That metal sheild is directly connected to the electrical GROUND on your MB and thus to the Power Supply ground.

There is a small fuse surface mounted on your MB that will blow if the USB port gets a blow that may cause the 5V pin of the USB jack to short to the metal sheild.

Unfortunately the fuse is impossible to replace unless you have access to surface mount technology. Also, to make matters worse, when such a short occurs it usually burns out a few associated components and often burns up some of the fine electrical traces on the motherboard.

I've had the occassion to replace six or seven MB's for people that needed computer repairs.

PS: I got my diploma in Electronics Technology in 1972 and worked as a communications tech for over 30 years. (Now retired, but still keep up on the latest developments)

PPS: Sorry I couldn't give you better news.

 

[lodingi]

Don't be sorry. I appreciate your accurate & thorough response. Thank you for taking the time to explain it.

Ugh. Now off to find a mobo.

 

[Old Hippie]

The USB jacks on the MB all have a metalic sheild that goes all the way around the connection for the nine pins for signal and +5Volts. It's designed to provide sheilding to prevent electrical noise to other devices, whether they be onboard the computer or any other device such as a nearby radio receiver or TV set. That metal sheild is directly connected to the electrical GROUND on your MB and thus to the Power Supply ground.

There is a small fuse surface mounted on your MB that will blow if the USB port gets a blow that may cause the 5V pin of the USB jack to short to the metal sheild.

Unfortunately the fuse is impossible to replace unless you have access to surface mount technology. Also, to make matters worse, when such a short occurs it usually burns out a few associated components and often burns up some of the fine electrical traces on the motherboard.

I appreciate the info.

Thanks!

 

[Jorona]

Can you see any physical burning on the board? When that fuse goes, its usually obvious... and smelly.

 

[Draxanoth]

There is a small fuse surface mounted on your MB that will blow if the USB port gets a blow that may cause the 5V pin of the USB jack to short to the metal sheild.

Could he short it again and reboot his machine more than once if the fuse is toast? I would have thought the circuit would be broken if the fuse is gone.

On a recent boot, I accidentally hit my wireless adaptor.

Did you whack it hard enough to jiggle the cables in the back? I'm wondering if your problem might be with one of those connections, a short inside or a faulty USB device, and the front just seemed most likely because that's where you physically touched it when it happened the first time.