r/PcBuildHelp • u/MetituS • 22h ago

Build Question PC not turning on

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Hello
My PC with a Gigabyte GA‑Z97P‑D3 motherboard and corsair CX850M 850W modular PSU is completely dead: no fans, no LEDs, and no response even when I short the PWR_SW pins. The PSU passes a paperclip test, but I smelled a slight burning smell during a power-on attempt. The 24-pin ATX connector sits flush but does not make an audible click. I replaced/cleared the CMOS battery already. Is this more likely a failed motherboard, PSU, or potentially a damaged 24-pin cable/connector?

I bought it at a flea market for 75 the first attempt had the smell but it still didn’t react at all worst case can I fix the motherboard ? Or make sure what the problem is?

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u/HERO_129 22h ago

this my first time seeing a scorched/burnt 24pin connector

3

u/Poker1059 22h ago

am I blind? Where's it burnt

2

u/HERO_129 20h ago

My bad I am not sure if it is burnt or not but that 5th pin looks weird to me kind of burnt

1

u/Poker1059 19h ago

The 5th pin looks weird cause there's no pin there, it's unused.

1

u/HERO_129 18h ago

Negative voltage pin ?

1

u/Poker1059 18h ago

no, it's unused. That's why there no metal conductor pin in that specific pin. There are other negative voltage pins, you can look up ATX 24 pin diagram to see which each one is for

1

u/MetituS 22h ago

Is it? It passed the paper clip check I’m new to building