New construction - CPU indicator light caused by faulty RAM?
New construction - CPU indicator light caused by faulty RAM?
Hello, I'm facing some tricky problems after upgrading my old PC—just swapped the CPU, motherboard, and RAM. Everything seemed fine before adding the power supply. I've built two previous setups and feel confident about the assembly. During the first boot, no video appeared (internal graphics off) and the red CPU debug light stayed on while fans spun. I don’t have a motherboard speaker. I checked various forums and found similar steps, but everything looked correct. The CMOS was reset and everything felt normal. I suspect the motherboard or CPU might be faulty. A repair shop confirmed it too—they think either the CPU or the motherboard is dead. I bought a new motherboard and installed it, but the CPU debug light stayed lit when powered on with no display. The RAM stick isn’t seated properly on the board, which I thought wasn’t a big issue, so I’m planning to replace it tomorrow using a kit from the QVL (Kingston Fury Beast 3200 CL16). It’s odd that memory is the problem when only the CPU shows the debug light. Could this be typical? Any advice would be appreciated.
I'd be more wary of the PSU than the RAM. I've noticed RAM can trigger CPU error codes occasionally, though rare. With an older PSU, it wouldn't be surprising if it caused issues on the 12V EPS rail. Consider swapping the RAM if you're serious, but I think that's unlikely to be the main issue.
Use a multimeter to verify if the PSU is the source of the issue. If the PSU is faulty, you'll notice a voltage drop on the EPS connectors during startup. You can test this by connecting an 8-pin plug and measuring the voltage from an unoccupied +12V pin to the unoccupied ground pin using the multimeter. A drop below 11V when powering up indicates a PSU problem. If no drop occurs, the issue may be elsewhere but is less likely.