PC won't start when GPU is plugged in after waterblock installation

diamantn

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May 5, 2014
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Hello guys!
So here is my problem, and I will try to explain it as clearly as I can.

A few weeks ago I started this little project, which was a wall mounted computer, also watercooled.
But when I was about to boot it up to fill the loop it wouldn't start. At first I was really shocked becuase I was so sure that it was gonna work, because I thought I did everything correct.

I doublechecked the cables and everything and I couldn't find anything wrong. So I started to troubleshoot this damn thing.
I started to test the power supply by doing the paperclip test, and it worked just fine.
I then tested the motherboard by connecting a fan to it and starting it up, and it worked just fine.
So I assume that the graphics card is dead or something. So I tried an old card and it worked just fine.

So the problem comes up when I connect the 6+8pin power connectors to the graphics card that I can't boot, in other cases it works just fine. The graphics card can be plugged in the PCI-e slot and it's able to boot. It's just when I plug the power connectors in.
Any ideas what can be wrong? Because I was really careful when I installed the waterblock, but I probably damaged it somehow?

EDIT #1:
I tried without the 8 pin connector to see if it would start and it did. Can it be something wrong with that?

And I tried clearing the CMOS as I read in another thread,

I have a MSI GeForce GTX 780 if you're wondering.

TLDR:
When I connect the 6+8 pin connectors to my graphics card the computer won't boot. In other cases it's working just fine (tried with an old card). Also tested the PSU and motherboard and they seem fine.
 
Solution
hmmm in that case it's either the GPU, but could still possibly be something with the PSU

It might not be delivering enough power on the 8 pin connection, but I wouldnt know how to test that other than having another 8 pin GPU to test out


I have the Corsair AX760.

But I just think it's weird that when I connect the 8 pin it can't boot. Wondering if there's something wrong with the cable..
 


1, Yes it is.
2. Yeah it's fully inserted.



 



I tried an old gpu so it doesn't have any connectors, so that sucks. Just did it to try the pci-e slot.

And I installed watercooling for the CPU and GPU.

 
i'm never had any experience of water cooling GPUs, but it certainly sounds like the GPU has developed a problem

I'm assuming you fitted a water cooling heatsink to the GPU? if so, that has probably invalidated any warranty the gpu might have had

Does any power come on at all (mobo led's, fans etc), or is it that when the GPU is connected to the PSU it doesn't turn on at all?
 


Yeah I think that you brake the warranty when you do this.

Yeah I can start it up and the fans are spinning and stuff like that. It's when I connect the 8 pin connector to the GPU that nothing works. Tried to just boot it up with only the 6 pin and it worked. But not when I plugged in the 8 pin.
 
hmmm in that case it's either the GPU, but could still possibly be something with the PSU

It might not be delivering enough power on the 8 pin connection, but I wouldnt know how to test that other than having another 8 pin GPU to test out
 
Solution