F5F Stay Refreshed Hardware Desktop PC fails to power up because the 8th pin connection isn't working

PC fails to power up because the 8th pin connection isn't working

PC fails to power up because the 8th pin connection isn't working

G
GameBoosh
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11-04-2025, 08:37 PM
#1
I've been struggling with my PC lately. It mostly happened after I powered it off last night. The system shut down quickly, and both the RAM and MOBO indicators stayed lit—unusual for me. When I tried to restart, it wouldn't boot at all. After some testing, I discovered a few things: 1. The PSU fan spins when you press a paper clip on it. 2. Powering on with the 24-pin connector works; the CPU LED debug light stays on, fans spin, and RGB lights come on. 3. It also boots when I connect both the 24-pin and the PCI 8 pin on my GPU. Both PCI-E power ports on the PSU are functioning normally. 4. If I plug in my CPU in the 4+4 slot or the 8 slot, it still won’t turn on—just two clicks, then the RAM RGB lights up after a short delay. My guess is that either the CPU, MOBO, or PSU has failed, but I don’t have spare parts to replace them right now. I’m hoping to get a new PSU and run some tests tomorrow, but I’m not sure what to do next. Thanks for any advice! Also, note that my CPU had the classic AM4 issue of coming out with the cooler during thermal paste changes a few years back—some pins were bent slightly, but I fixed them and everything worked again.

Specs: CPU: 3700X RAM: 2x8GB 3600MHz Corsair Vengeance Mobo: X570 Aorus Pro GPU: Gigabyte 2070 Super Gaming OC (probably) PSU: Corsair TX750M
Updated: Took my rig to a local repair shop; it seems the motherboard died. I ordered a new one and will update once it arrives. Final update: got the new board and everything is functioning properly now.

Edited December 12, 2025 by juliotulho
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G
GameBoosh
11-04-2025, 08:37 PM #1

I've been struggling with my PC lately. It mostly happened after I powered it off last night. The system shut down quickly, and both the RAM and MOBO indicators stayed lit—unusual for me. When I tried to restart, it wouldn't boot at all. After some testing, I discovered a few things: 1. The PSU fan spins when you press a paper clip on it. 2. Powering on with the 24-pin connector works; the CPU LED debug light stays on, fans spin, and RGB lights come on. 3. It also boots when I connect both the 24-pin and the PCI 8 pin on my GPU. Both PCI-E power ports on the PSU are functioning normally. 4. If I plug in my CPU in the 4+4 slot or the 8 slot, it still won’t turn on—just two clicks, then the RAM RGB lights up after a short delay. My guess is that either the CPU, MOBO, or PSU has failed, but I don’t have spare parts to replace them right now. I’m hoping to get a new PSU and run some tests tomorrow, but I’m not sure what to do next. Thanks for any advice! Also, note that my CPU had the classic AM4 issue of coming out with the cooler during thermal paste changes a few years back—some pins were bent slightly, but I fixed them and everything worked again.

Specs: CPU: 3700X RAM: 2x8GB 3600MHz Corsair Vengeance Mobo: X570 Aorus Pro GPU: Gigabyte 2070 Super Gaming OC (probably) PSU: Corsair TX750M
Updated: Took my rig to a local repair shop; it seems the motherboard died. I ordered a new one and will update once it arrives. Final update: got the new board and everything is functioning properly now.

Edited December 12, 2025 by juliotulho

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