# Short Circuit when plugging in Display cables into the Graphic Card



## BlackRaio (May 20, 2016)

Hey guys,

after almost 1 month of trying to solve the problem on my own, i am now desperate for help in this case. So i would be really glad if anyone could point me in the right direction.

*Current PC Setup*

•	CPU: Intel Core i7-3930K
•	Motherboard: MSI X79A-GD65 (8D)
•	CPU-FAN: Noctuna NH-C12P SE 14
•	16GB RAM
•	GPU1: NVIDIA GTX 980 TI MSI Gaming 6G
•	GPU2: EVGA NVIDIA GT 610
•	PSU: Corsair 1000HX
•	5 different Displays (Displayport x2, HDMI x2, VGA)
•	Outlet Strips with overvoltage protection

*What happened before?*

A few weeks ago i tried to connect a display to one of my graphic cards. Today i cannot recall the exact failure on my side, but i got a big short circuit for connecting one of the former DVI cables into my former GTX 680 graphic card. Same second the fuse got tripped. Since this moment an odysee began.

*How i tried to fix it*

1.	First i thought it would be just the broken graphic card. The GTX 680 was definitely grilled and not working anymore. My 980 Ti started the PC and was fine, until i tried to load a graphic needy program. Then the driver crashed or the PC instantly rebooted / bluescreen (nvlddmkm.sys). I replaced both graphic cards with the ones above in the setup (refurbished or new).

2.	I also checked my former Corsair 750HX on errors. A PSU tester showed me, that all Volts were perfectly okay, just the PG was 0ms. Better be safe than sorry i thought and replaced it with the new one above.

3.	All Monitors are perfectly working elsewhere, so they are not the issue.

4.	I grounded myself for all the working to make sure i am not being myself the problem.

5.	I checked all cable connections. Cables are fine, all connected correctly for sure and exactly like they were before when it was working.

*What happens now?*

After taking all these steps, i finally thought this should be it and all will work again. Nope. As soon as the VGA cable from my monitor touched the metal of the (new) GT 610 i again got a short curcuit and the fuse tripped. Power of PC and Monitor were both off and i am pretty sure even when i plugged all out, i will still get this (observed that one time before i took all these measures above). Now i am pretty devastated and not sure what to do. Ofc i am afraid to plug in anything buy now, afraid of destroying any more of my pc parts (after already replacing them...).

My next and last guess would be, that with the first (for whatever reason) short circuit the Motherboard got damaged in any way. Remember that my PC (before taken the measures above) still worked with my 980 Ti (even if not with games or anything) and with various monitors. The 980 Ti also worked on different PCI-E slots, also on the PCI-E where normally the short circuits happened. But that might be no indicator for it's non-malfunction?

To be honest i do not like the thought of replacing the Motherboard too, because the i7 3930k is not fitting in any new Motherboard Sockets and the old 2011 Sockets are hard to get ANYWHERE (for me in germany). So it seems like it would be a new Motherboard + CPU, which would be also a waste for the perfectly fine CPU.

Sorry if i did not support you with all the informations you needed, pls feel free to ask anything you need to know. You see that i know my way around most things, but i am by far no expert for anything. I would be really glad for any help you guys can shoot me.

Thx in advance,
BlackRaio


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## Aus_Karlos (Mar 10, 2007)

Welcome to TFS,
Usually the little bit of a spark from the DVI/VGA/HDMI ect can be the potential voltage equalizing between the components.
If its tripping your houses RCD (Residual Current Device) make sure both the monitor and PC share the same socket outlet. Having them on 2 different socket outlets could mean they are on different circuits altogether which can cause tripping.
Also the Corsiar 1000W is a very hungry power PSU make sure your not overloading your house Power Circuit by having too many high powered appliances on the same one.


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## BlackRaio (May 20, 2016)

Huh, it's true that my Monitors and my PC are not all on the same socket outlets. And the Monitors which were working before, WERE on the same socket outlet. HUH. That seems pretty reasonable! Nothing else is really turned on in this house circuit, so i am pretty sure there is all fine. Just not wanted to have i all on one circuit. Maybe i should have...

But can it even happen when the socket outlet for the monitor was turned off? PC also was turned on zero. 

(Thx so far for this tip!!!!)


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## jimscreechy (Jan 7, 2005)

I am inclined to believe that either your monitor or your PC are not grounded properly. One will be at a higher or lower potential and when you connect them, the resulting current flows (as Aus Karlos says) between them to equalise the voltage or reduce the Potential difference.

This is a very common problem with PC's when connecting to USB devices powered by an adaptor with only two pins (or three pins where only 2 are connected) when the earth is plastic, not connected, or with UK plugs an unconnected 'dummy' to allow the plug to be inserted in the socket you don't have a true earth and it can cause problems. Generally these tend to be newer "Double insulated" power supplies which tend to be 'Switched' and are quite frankly a pain in the neck. What you end up with is a 'floating earth where the potential of the negative, sleeve, or housing connector is nowhere near 0v where it should be. Sometimes this can be many tens of volts above or below 0v. If you have ever plugged a USB device like a external hard drive that has its own power supply into a PC and see a spark, then this is what is taking place. In fact motherboard manufacturers are well aware of this issue and design their boards with this phenomenon in mind implementing many measures to ensure such conditions don't 'take out' their motherboards and render any additional components useless.

PC power supplies have a true earth where earth wire is connected to the chassis which when mounted to the case also provides the same 0v potential. I am not sure about the requirement for monitors but all I have encountered, (even the new ones) also have true earth. If one of your earths is disconnected, or becomes disconnected, either at the device, lets say a wire becomes detached, or because the house socket it is connected to is not earthed for some reason, then you get miserable consequences. Current will flow from the non earthed device through the connecting cable to the earth of your pc often with unfortunate consequences. I should also add that this can happen when a device appears to be working perfectly with other devices which may have a higher tolerance. It can also happen with a device that is earthed but has a fault which is sending a voltage on signal cables which obviously shouldn't be there... which is hard to diagnose. 

At any rate if you have a multimeter your first test is to use the resistance setting to ensure the chassis of your pc is directly connected to earth. Do the same for all your monitors. I may be a little more difficult for the monitors as they tend to shrouded in plastic these days but test between the end of the plug and any bare metal casings or the shield its connectors.


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