Strangest USB Problem - Tripping PSU

Tesla

Tesla

Tesla

Soldato
Joined
19 Jan 2003
Posts
17,601
Location
Bristol, UK
I have come across one of the most strangest problems to date with my AV/PC business.

One of my customers had a PC that was randomly swithing off and crashing after he had installed a DVD-RW.

I disconnected all of the hardware and reinstalled it which cured the problem ( I didnt remove parts from the case, just reconnect). Initialy I disconnected them to find out the culprit by process of elimination but they all went back together working fine and he reports that it has still not crashed or switched off. I guess he disturbed something when connecting the DVD-rW drive.

He however has reported a new problem. When connecting aything, including just a USB A-B cable to a USB port the system will power off. I have spoke to him on the phone and had him try different ports and the same thing happens.

There are other USB devices connected and running fine.

Any ideas, sounds like a power related issue, possibly shorting out but it doesn't explain how everything else is working fine and he isn't actually connecting a device.

Appreciate any advice,

Chris
 
kmistry said:
Hmm that is a weird problem, perhaps you have another PSU that you could try out ?
Click to expand...
Thats the only thing I could think of. I am ringing him back this afternoon and will probably pop round and give it a go.
 
Sounds like a psu and earthing / shorting problem, but it could well be something to do with the mobo southbridge as all the devices u mentioned are controlled from there.
 
Same problem here.
On the weekend I fitted a 2nd DVD Writer and the machine wouldn't start up. It was like it was hanging before it got to the BIOS screen i.e. the CPU fans etc were spinning but no beeps. Turning the mains off and turning on and off the power supply switch seems to cure it.
I just plugged in the basic things i.e. keyboard mouse etc and it works fine. It's only when I plugged in the additional USB items i.e. Remote wonder wireless that I get the problem.
Weird or what!!!
 
happy_2008 said:
This happened to my work pc for some strange reason, it hasnt happened since thou. I plugged in a flash memory stick and the bloody thing restarted.
Click to expand...

Does the work pc have a MSI mobo by any chance.
 
What PSU?
My first thought would be a tinpot PSU simply failing to cope with the load its being put under. I'm assuming this is a simple office machine, and so lack of power problems are going to show up less often than in a heavily stressed gaming machine.
If the working device is plugged into a rear IO plate port, and he's tried another of these, then again I would point the finger squarely at the PSU- If its an earthing issue, then it would affect all of the ports on the same bit (Sorry, can't think of a better word :p ) as opposed to just one of these.

-Leezer-
 
i had the same problem, the plastic block in the usb port had snapped off, this lead too when i put in a usb device id sometimes short out 2 pins, thus leading to the psu to trip
 
Tesla said:
Are USB (infact all I/O) ports grounded through the I/O plate?
Click to expand...

As far as I'm aware, no.
There is at least one ground pin in any port; I'm not precisely sure where this connects to, I would assume the PSU ground.
I/O plate or lack of it should make absolutely no difference whatsoever. My server is also running perfectly happily using rear USB & some others with no I/O plate.

-Leezer-
 
leezer3 said:
As far as I'm aware, no.
There is at least one ground pin in any port; I'm not precisely sure where this connects to, I would assume the PSU ground.
I/O plate or lack of it should make absolutely no difference whatsoever. My server is also running perfectly happily using rear USB & some others with no I/O plate.

-Leezer-
Click to expand...
Thanks for clearing that up mate.
 
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