Graphic cards get destroyed in the PC, where is the problem ?

[stromojed]

Hi,

one day it simply turned off and is not possible to turn it back on. The PSU is immediately shutting down. LED on MB is indicating it is getting power, power outlet is ok, power source seems to be ok – checked volts on all connectors and is turning on and off normally (when it is alone).

Here is my configuration:
MB MSI P35 Platinum – all solid capacitors
CPU Core2Duo
PSU Seasonic 500W – all solid capacitors or heavy duty
GPU nVidia 8800GT

The PC starts for fraction of second, fans move a little, that is all. When graphic card (GC) is unplugged, PC starts normally – just POST stops since there is no GC (indicated by leds on MB).
I thought the GC is finished and bought the new one. (Radeon HD7770) After replacement, computer worked for 2-3 minutes, then turned off and the same situation repeated.
Further investigation showed:
- Both GCs are faulty – there is short circuit on auxiliary power connector – this explains why PSU shuts down immediately
- PSU and MB seems to be functional
- Visually is everything ok, nothing burned on MB, GC or inside PSU

Where might be the problem, any clue? Just replacing by another GC is probably not a solution, it might be “burned” again. I know there is still chance that it is just a coincidence and the new card was faulty.
The intriguing question is how MB or PSU can destroy GC, especially so that short circuit is created on auxiliary power connector on GC. How to find out if the problem is in PSU or MB ?

Michal

 

[Max1s]

I dont think its the graphics cards. Try resetting your bios.

 

[stromojed]

It is graophic cards, the problme is that not only graphic cards.
Both grahic cards ware tested in 2 other computers with the same result - unable to start, PSU shuts down.
One other working GC has measureable resistance on auxiliary power conector between +12V and GND, so it is not right if the resistance is 0 and on the faulty cards.

 

[stromojed]

I found partly deffective 8800GTS displaying artifacts, so it will be no loss if it will be destroyed during testing. It is now running for more than 5 hours. SO it cound have been just coincidence after all, I will try to find some fully functional old card to test.