Hi! I just sold my used EVGA 1080ti card (11G-P4-6591-RX) but when I plugged in my pc to test before shipping to buyer, a weird thing happened:
 
- If I plug the 6 and 8pin pcie cables to the card, nothing happens when I try to power on my pc (only my rgb ram sticks light up, but everything else is dead. The "M" led indicator in card keeps blinking red).
- If I remove both 6 and 8 pin pcie cables the system boots as it should (until the point a black screen appears asking to plug in pci-e power cables).
- If I remove only the 6 pin cable system boots as it should (until the point a black screen appears asking to plug in pci-e power cables).
Summary: If the 6 pin cable is plugged in, the pc wont boot at all (only my rgb ram sticks light up, but everythin else is dead. The "M" led indicator in card keeps blinking red).
 
This card was working flawless until my new card arrived (3080) and I removed this old one and it was sitting in a box in my closet for +- 4 months. A few things I tried:
 
- Clear CMOS
- general card cleaning (only with a brush and eraser, as usual)
- Different psu cables coming directly from PSU. I have a corsair TX750M
- Using a spare cable that came with the 1080ti (molex -> 6pin cable). Nothing works....
 
I put my 3080 back and my pc boot as it should, so I don't think there's anything wrong with my pc parts. I'll try to test this vga in another computer tomorrow.
 
I'm assuming there's something wrong with 6pin circuit, maybe? I have a multimeter at home but don't know how to test the board.
 
Thanks,

EVGA GeForce GTX 1080 Ti iCX GAMING, 11G-P4-6591-KR
 
Your corsair TX750M PSU exceeds the 600W minimum (see specs in link above)
 
Did you buy an extended warranty, for your original GPU?
 
confirm 1080 Ti is fully seated & locked in PCIe slot & that PCIe power cables are fully seated & locked/latched in the GPU power socket
 
I like to push on the wires & not the plastic end on the PCIe power cables, to help make sure none of the pins in the plastic backup while assembling, while I also supporting the GPU when pressing the cables in.