Initial setup scare: Asus Prime X399-A motherboard not powering up?
Initial setup scare: Asus Prime X399-A motherboard not powering up?
It would really be a big problem if I received a defective MOBO during my first attempt, especially since I’m not familiar with troubleshooting. Because everything was set up correctly, yet when I turned on the PSU and pressed the power button for the motherboard, nothing happened. The fan didn’t spin, and only the RGB lights remained active. I removed the 24-pin ATX cable from the PSU to the motherboard, which stopped the RGB display as expected. This suggests the power reached the motherboard but not the motherboard itself. It seems my PSU is working, but not the motherboard. Should I expect my fans to turn on if I power on the motherboard instead of the PSU? None of my fans—case fans, CPU fans, or even the case—are spinning. I’m hoping this isn’t a coincidence, especially given Asus’s reputation. Could anyone assist me?
For reference, here’s what I received:
- CPU: AMD Threadripper 1900X 3.8GHz (8-core) – $449
- Cooler: Noctua NH-U14S TR4-SP3 – $79.90
- Thermal paste: Gelid GC-Extreme 3.5g – $12.89
- Motherboard: Asus PRIME X399-A EATX – $330.89
- RAM: Corsair Vengeance LED 32GB (4x8GB) – $354.99
- SSD: Samsung 850 EVO 1TB – $289.99
- GPU: Zotac GeForce GTX 1080 Ti 11GB – $1128.03
- Case: Corsair 750D Airflow ATX – $154.65
- PSU: Corsair RMx 1000W (80+ Gold) – $169.78
- Network: TP-Link TG-3468 Wi-Fi – $69.99
- Monitor: HDMI connection only
Additional notes:
1. A steady orange/amber light labeled “SB_PWR” is always on.
2. Q_Code LED isn’t working, making diagnosis harder.
3. I linked my monitor via HDMI instead of VGA.
4. The manual said connecting the PSU directly to the GPU wouldn’t help, so I tried a PCI 8-pin cable and a 6+2 + 6 pin setup.
5. My Zotac GPU didn’t light up, even though I used a blower edition, which is confusing since I wasn’t sure about its behavior.
I’ve tried several fixes: jumping the power buttons, using full cables, connecting RAM by port, and even following the manual step-by-step. Still nothing. It’s frustrating, especially after investing so much time. Please help!
Regarding the 4-pin connector in the first photo, it appears unused. As for the CPU, it has been fully secured according to the tool's instructions.
I connected it after plugging it in and tried again, but the issue remains unchanged. Are you referring to the three screws secured with a Torx screwdriver? I believe I’ve tightened them well enough so they won’t come out easily by hand, though I can’t verify that now since the CPU fan is visible on top.
I might attempt to take out some components from the case, because the case can sometimes lead to a brief issue. Also, remove all parts from the motherboard except one RAM stick, the ATX power supply, the CPU power, and the graphics card along with its power source. If this doesn’t resolve the problem, you could be dealing with a faulty board since the LED error code won’t activate.
Usually removing the 4-pin connector won’t stop you from seeing power, but it won’t show a post. Same goes for faulty RAM or GPU—same with bad CPU: the fan will kick on and stay at full speed, which feels like a motherboard or power supply problem (unless you missed something). If you can’t find the issue, try a different PSU, and don’t worry, people often suggest simple fixes.
I also noticed something quite alike while working at Acer's refurb factory. The PC wouldn't post, there was no power indicator in the case, but when I took it apart and placed it on my desk, it worked fine. I asked for a replacement case during the disassembly process and everything functioned properly.
I feel a sense of caution suggesting you look beneath your cooler for any residue from the paste, just in case you overloaded it. You might also want to reinsert the CPU again—worth a try if it didn’t fit properly before. If you’re missing any RAM slots, give them a test run. Honestly, it seems like you’ll probably need to return the item for replacement.
Same issue encountered. Cause: Power supply features four 8-pin connectors—three VGA (6+2) and one CPU (4+4). These connectors share many pins, fitting into identical sockets. Fix: - Disconnect VGA (6+2) connectors from the motherboard. - On the motherboard’s 8-pin socket, attach the CPU (4+4) connector. - Leave the 4-pin socket unused.
You're experiencing the same issue again with your Threadripper 1950x. The power supply seems fine, and you've already replaced the motherboard within a month. The standby light is still orange, and the PC won't power on. It's been a long wait for this build, but the problem keeps coming up. Any tips or alternatives would be helpful.
I face identical problems with the same issues, x399-a and 1920x. Only a 750w PSU is available, and the 8-pin power is connected, though the manual says the 4-pin is optional. The device posts once during initial testing, but after being placed in the case it stops working. I’ve removed all components for a bench test, yet nothing happens.