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Question Motherboard dead after connecting PCIe power to CPU power

makskolis

Prominent
Dec 7, 2018
4
0
510
0
Hello,
Recently I got a new graphics card for my birthday (GTX 1050 Ti) and bought a new power supply along with it due to the old PSU's cables not being long enough and the old PSU not being powerful enough

(System specs at the bottom)

I connected everything and hit the power button. Nothing happened.
I soon realized what might have been the issue. I accidentally connected the PCIe power (6+2) to the CPU power socket on the motherboard instead of the CPU power cable (4+4)

I tried the old power supply (no graphics card this time) and nothing happened.

I suspect the motherboard has failed due to my motherboard having four LEDs that light up during POST and blink if something has gone wrong.
None of the POST debug LEDs lit up so i think only the motherboard was fried. If only the CPU got fried and the mobo was fine, the CPU debug LED would have blinked.

I have two final questions:
Was my assumption (mobo only, CPU fine) correct?
Can I trust the new PSU after connecting it incorrectly? (specified above)
Note: The old PSU was wired correctly (100% sure)
Is my GPU going to be fine? (It was inserted when I connected the new PSU incorrectly)

System specs:
Motherboard: Msi H310M Pro-VH
CPU: Intel Core i3 - 8100
Old power supply: CiT Pentium p4 (300W, known good)
New power supply: Kolink KL-C400 (300 - 400W, not sure)
GPU: GTX 1050 Ti
 
Old power supply: CiT Pentium p4 (300W, known good)
New power supply: Kolink KL-C400 (300 - 400W, not sure)
Unfortunately, both of these PSUs are particularly poor, poor quality. A good quality PSU would have "seen" that the polarity was reversed at the connection (PCIe is "opposite" from EPS12V) and would have shut down when the output impedance is < 0.1 Ohm.

Can you tell if the PSU itself is still working? e.g. Can you "jump start" the PSU with a paper clip and see the fan spin?
 

makskolis

Prominent
Dec 7, 2018
4
0
510
0
That signifies nothing more than the PSU can power itself.

Connecting the wrong things together and powering up...likely you let the magic smoke out of something.
I'm definitely going to buy a new motherboard as that probably failed.
I might take the power supplied to some of the local phone and pc repair shops to see if they can test the supplies.
 

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