Any help would be so appreciated. My son and I recently put together a desktop from parts. Was working amazing for 3 weeks, then suddenly froze for the very first time. Did a hard shutdown, but when turning the desktop back on, it powers for about 4 seconds, all components light up, then reboots before the monitor displays anything. The ASUS motherboard (ROG STRIX Z-690g manual) shines its Q-LED red light for CPU for half a second, which I think indicates CPU is good. Then it shines its orange light for about 3 seconds, which I think indicates RAM is good. Then nothing shines for half a second before machine reboots.
I've been trying to diagnose, my son really needs his computer, but it's difficult because I don't have spare parts. I have to purchase new parts just to test. And the difficulty is compounded because this computer has hard-tubing liquid cooling that is super difficult to deal with (next computer we're doing something different!). These are the steps we tried:
- Unplugged graphics card. The RTX 4090 SUPRIM LIQUID X is also liquid-cooled but comes with its own separate radiator. I was thinking that unplugging it would tell us whether it's at fault or maybe it was drawing too much power from a weak power supply. However, the problem persisted with the GPU out of the system.
- Reset CMOS by pushing the reset CMOS button on the back of the computer where ports are. Tried pressing it for 1 sec, 5 secs, 10 sec, 15 secs, 30 secs. With no power, with power, with no power but still plugged in. Nothing helped.
- Bought a new power supply, exactly the same Silverstone SX1000 Platinum. Problem persisted.
- Swapped DIMM locations (DDR5-6000, I had to set the XMP profile in BIOS previously), unplugged 1 of the 2 DIMMs, swapped which DIMM was plugged in, tried the B2 slot instead of the A2 slot. With only 1 DIMM, the orange light only stays on about 1.5 seconds, but rebooting comes shortly after, as before.
- Tried no RAM. This time orange light stayed on indefinitely and the computer never reboots. Nothing ever shows up on the monitor either.
At this point I'm guessing it's a bad motherboard. But I really have no idea. I guess it could be that both DIMMs suddenly went bad? I'd imagine a bad hard drive (Samsung 980 Pro 2TB) would still allow the system to boot? The tubing makes that difficult to get to. Could be the CPU (core i9-13900k) went bad? That would be a pain with the liquid cooling. But the Q-LED lights seem to indicate that the CPU is good.
What's the best move that will optimize my ROI? These parts are too expensive! I'm about to buy another motherboard as I'm guessing the probability of both DIMMs going bad or the CPU or SSD causing these problems is very low. These motherboards are expensive and it is such a pain with this hard tubing. So before I take this next step, wanted to see if there's something I'm missing or some easier thing I should try first.
Just to give an idea of the pain of this liquid cooling, the hard tubing was so difficult to deal with in this case, but we got it. To replace the CPU, motherboard, or maybe even the SSD, I have to drain all the liquid thoroughly and flush it. Then disassemble, reconnect all, buy new liquid coolant, and go through a whole process of replenishing the liquid. And after all that, maybe the system still reboots! I could test the system without reassembling the liquid cooling, but I understand that could damage the CPU and doesn't function long anyway (maybe not long enough to test?). I could buy a CPU fan/heatsink too for testing.
