New used part setup. Device won't power down and restarts on its own.
New used part setup. Device won't power down and restarts on its own.
I've assembled PCs since the early 90s and haven't faced a problem like this before. I created a budget setup for retro game emulators. All parts were sourced second-hand from eBay, except the case, power supply, SSD (Gigabyte GA-B75M-D3H), i5 2500k CPU, 16GB RAM, Corsair XMS3 DDR3, TeamGroup GX2 SSD, and Corsair CX550 PSU. I just completed the build last night. As soon as I flipped the power supply switch, the system started booting. I thought maybe I misconfigured the panel switches. I reset to default settings and restarted, then installed Windows 10. After shutdown, Windows closed but the PSU, fans, and CPU cooler kept running. I had to flip the power supply switch to fully power off. When I did that, it booted up automatically. I removed all front-panel switches, but it still auto-booted. Shorting the power switch pins didn't resolve the issue. I pulled out the graphics card and connected a monitor directly to the motherboard. The same problem persisted. I disabled Windows Fast Boot, but it didn’t help. Unplugging the SSD also didn’t fix it. The PSU is new from Newegg, though it might be faulty. I suspect the motherboard could be the issue. Everything seems functional except for the inability to shut down completely without flipping the switch. Should I just accept this? Is it likely the motherboard needs replacing, or are there other steps I should try? Thanks.
Consider removing power from the internal parts (just take out the plugs), turn on the PSU switch and see if the fan begins rotating—this helps determine if the PSU is starting independently or if the motherboard is initiating it. You might also test a different PSU; identical results suggest the issue lies with the motherboard.
I changed the RAM module...still same problem. I unplugged the PSU from all connections. When I flip the switch, it powers on. Verified by connecting a fan to MOLEX and it lights up and runs, so the PSU starts automatically and doesn’t shut down. This behavior hasn’t happened before.