The consequences of plugging in a USB cable the wrong way

I tried to plug a USB cable into my computer's USB card upsidedown (I thought it was rightside up) and when I tried to force it in, the computer shut down by itself. I hit the power button and it didn't come back on. I turned off the master power for a few seconds, then tried again and it came back up. So I learned a valuable lesson: Don't try to force USB cords in the wrong way.

 

Perhaps we should add to this not to try and modify usb cables.

I had a 'friend' modify a usb A cable to fit into a proprietary slot on a device. He plugged the cable into the pc and then 'persuaded' it into the device; installing the cable upside down as it turns out. PC shut down as soon as he made the connection and his USB ports on the M/B have not worked since.

Since on a USB A cable Pin 1 is +5V DC and Pin 4 is ground, flipping the cable switches the 'hot' and ground contacts shorting the power supply.

If fortunate, just removing the offending cable and unplugging the machine for a couple of minutes will allow the comptuer to turn back on. Sometimes, as he found out, the damage can be more extreme.

It's amazing what unknowing users will try and modify to work on their PCs. It never occured to my friend that if the cable looked nothing like the recepticle on the device that it wasn't supposed to fit.

It also reminds me of an electronics place I used to work at. I had an eldery gentleman show me his 'homemade' cable splice. He bought a USB printer with no USB port on the comptuer. He had stripped and tried to splice together a Parallel cable and USB cable. It was quite a mess. Wish I had taken a picture!!

Cheers,

ICE

 

LMAO OMG. The thing is, I'm not ordinarily that n00bish. I thought I had the **** thing right. I should've doublechecked it, then triplechecked to be sure. I'm lucky, the port works and my digicam is OK with it. A good, hard lesson.

 

I hope your digicam wasn't plugged in that cable when this happened. That could have been catastrophic. There's sufficient current to do some serious damage. I'm not sure if inserting it backwards creates a direct short or not.

A common mistake concerning USB is thinking that the usb pin headers on motherboards are all wired the same from mainboard vendor to vendor. They're not. I used to help out noobs alot by researching the pin config of the usb header on their mainboard.

My friend killed a motherboard and we determined it was because he used a usb bracket from a different mfr. I checked the pin configs and sure enough, the two mfrs. used different layouts.

Wow, Shadowhawk, I didn't think it was physically possible to do this. There's a plastic "stopper on one side of the pins. Line them up wrong and the two plastic stoppers would block each other and prevent insertion. Always keep the USB symbol either up or forward when inserting.

Gary

 

Thankfully it wasn't. I just sorta kept pushing it in. I may have dislodged the card a bit from the back of the machine. But it seems OK now. The thing is, I had to plug it in with the USB symbol facing down to get it to go. So I learned a lesson.