Hello everyone,

I'm building a gaming PC by myself for the first time and I would need help from the community. Here's the parts list: https://pcpartpicker.com/list/3dPKfd (no compatibility issues to be declared as far as PCPartPicker goes)

I've assembled the PC yesterday and when the moment came to turn everything on, I encountered failure on POST with BOTH CPU and DRAM debug LEDs staying on. More details:

• Everything properly plugged in
  • EPS in P8 — PSU-side — and ATX12V1 on MB side
  • ATX in the 24-pin
  • PCIe in the GPU
  • CPU cooler plugged into CPU_FAN1
  • DisplayPort connected to screen from GPU's port
  • RAMs properly seated, latches clicked fine (2x16GB, A2-B2 as advised in mobo's manual)
  • SSD in the M2.1 slot
  • Front panel connections
• At startup (turning the PSU on and then pressing case Power button)
  • Case fans and lights turn on, fans spin at full speed (note they're receiving their separate power straight from the PSU through a SATA cable, not from the mobo)
  • PSU fan spins full speed for a second and goes low-regime (I can feel the air underneath the case but there's very little sound)
  • Case Power button LED turns and stays on (I'm pretty sure it's receiving power from the motherboard)
  • CPU cooler fan DOES NOT spin (at all, and NEVER spun when plugged on CPU_FAN1)
  • CPU AND DRAM debug LEDs are lit red.

Now because I've heard about the DDR5 "memory training" first boot times being longer, I waited. I waited for 15+ minutes to rule that out, but nothing changed.

I did two other tests:

1. Removed the A2 RAM to leave only B2 (as advised in my mobo's manual, for single-stick configs) -> same.

Removed the GPU also because it was in the way and I'd rather put it back in when everything seems to work.

2. Removed all RAM to see if that would change the debug LED code: nope, still CPU+DRAM LEDs shining a solid red.

Attached is a photo of the motherboard inside the case at the current state, with removed RAMs and GPU, in case there's something obvious which I've missed.

https://preview.redd.it/6j9fvvjn9pyf1.png?width=1537&format=png&auto=webp&s=c465ec5395501fa6f6e00b43f0b755ec605527bb

Following the PC troubleshooting flowchart at https://www.reddit.com/r/buildapcforme/comments/1hfm6w2/is_your_new_pc_not_working_heres_a_flowchart_on/?utm_source=share&utm_medium=web3x&utm_name=web3xcss&utm_term=1&utm_content=share_button, I end up on the "BIOS flashback" step. My mobo is equipped with BIOS flashback and I don't mind flashing but I also know from the BIOS motherboard physical sticker that it came with BIOS version 3.10 which is very recent and WAY ahead of the minimal BIOS versions that I need for compatibility (1.24 for CPU, 1.28 for RAM, respectively), so I don't see how that could make anything different.

I have two questions about quite unlikely culprits:

1. Maximum supported RAM frequency by the 7500F is 5200 MHz. I know that a lot of people run higher frequencies with it though since it's a popular gaming CPU, and I'm sure it shouldn't be an issue at all... except maybe for the first boot ? before "OC" options related to CPU/RAM are turned on in BIOS ?
2. My RAM stick: "F5-6000J3238F16GX2-TZ5N" is not on the mobo's QVL. However its RGB variant "F5-6000J3238F16GX2-TZ5NR" is indeed on the QVL. One could only assume the non-RGB part would work exactly the same regarding compatibility, but please correct me if I'm mistaken.

Finally I've heard that CPU detection problems can arise when the CPU cooler is overtightened. I would doubt I f***ed that up: only turned the screw until the spring thing touched the CPU cooler mount, after which I turned an additional quarter of turn, if not less.

Can you think of anything ? Any help would be greatly appreciated.

Notes

To give you a little context, that's actually my 3rd weekend in a row where I'm shooting a shot at this, and I always encounter the same problem. My last 2 attempts were with a Ryzen 5 5500 CPU and MSI B550-A PRO with DDR4, and no amount of flashing BIOS versions, CMOS clearance, RAM stick switching, or CPU reseating could help me. Note: different manufacturer (MSI vs ASRock) so the debug LED system might be different but I only had the CPU light turned on back then, not the DRAM.

I decided to return the parts and switch for AM5/DDR5 for a more future-proof build, better support on parts that are more popular, and most importantly the AM5 switch to LGA, because I'd rather have the CPU less fragile.

After the first two attempts I wondered if the EPS connector was faulty and, with a multimeter, I checked for continuity in the connector as well as proper voltage delivery (~11.8V, I assume that's within tolerance) so the EPS connector should be ruled out. With the case fans and LEDs being powered, as well as the PSU fan spinning just fine, I would rule out issues related to the PSU (it's also a quality 80+Gold PSU). Some will say it's a low wattage PSU, but my system being estimated at around a 350 wattage, I believe 550W should be enough. Again correct me if I'm wrong. In any case, without GPU plugged in, power output should not be an issue.

I also tried plugging the CPU cooler into the case fans system, and it spun perfectly fine: I would rule out faulty CPU cooler (it not being detected would likely prevent the CPU from being powered on).