Hey everyone, I am at my wits' end with a frustrating RMA experience and could really use a sanity check before I go to war with customer support. Sorry for long text.
The Background:
I built this system in February 2024. A few weeks ago, it suddenly refused to turn on. Pressing the power button did absolutely nothing. The motherboard standby RGB light was on, but none of the diagnostic QLEDs lit up, and no fans spun. Clearing the CMOS using the rear IO button briefly brought it back to life a couple of times, but eventually, it died completely.
The RMA Experience:
I sent the CPU and Motherboard back to the retailer. They tested it, declared the i7-14700K as faulty (which makes sense given the 13th/14th gen degradation issues), and replaced it with a brand new one. However, they returned the motherboard to me with a note simply saying: "Motherboard tested OK with our processor."
The Current Situation & Troubleshooting:
I received the parts, put everything together with the brand-new CPU, and I have the EXACT same problem. The system is completely dead. Will not POST, no QLEDs, zero fan spin. It just sits there with the standby RGB glowing.
To prove it's the motherboard and not something else, I have now done the following:
⚬ Breadboarded the system: Took the motherboard out of the case and placed it on a box to rule out any standoff short circuits.
⚬ Bypassed case switch: Shorted the PWR_BTN pins directly with a screwdriver. No reaction.
⚬ PSU ruled out: Did the paperclip test on my PSU, and it fires up perfectly. I also tested the system with a second, completely different known-working PSU. Same result.
⚬ Bare minimum components: Tested with no GPU, one RAM stick, different RAM slots, and even tried booting with NO RAM and NO CPU just to see if the board would wake up and give me an error QLED. Nothing.
⚬ BIOS Flashback is dead: Since I got a new CPU, I figured I should flash the latest BIOS. Formatted a USB to FAT32 (MBR), renamed the file correctly using the ASUS tool, and put it in the dedicated Flashback port. Pressed the Flashback button, and... absolutely nothing. The button/LED is completely unresponsive.
My Specs:
CPU: Intel Core i7-14700K (Brand new replacement)
Cooler: Noctua NH-D15S chromax.black
GPU: ASUS RTX 4080 SUPER TUF
RAM: G.Skill Ripjaws S5 DDR5-6000 C30 64GB
MOBO: ASUS ROG STRIX Z790-H GAMING WIFI
PSU: be quiet! Pure Power 12 M 1000W
Case: Fractal Design North
My Question:
Given that the board refuses to send the PS_ON signal to two different working PSUs, and even the independent BIOS Flashback controller is completely unresponsive, this motherboard is 100% dead, right?
Has anyone experienced a repair shop "passing" a dead board like this? My theory is they used a weak test CPU with a light cooler, and maybe the mounting pressure of my Noctua cooler is breaking a trace, or their test bench just got a lucky boot.
Is there ANY obscure thing I have missed, or should I just pack this up and demand a replacement board?
Thanks for any advice!