I’ve have spent 2 weeks trying to get my Asus B250 Mining Expert mobo to boot with no success. I turn on the power and it shuts off quickly. Then 3 seconds later it tries again and shuts off again and it will repeat this behavior endlessly until I flip the PSU power switch off. If I unplug the 4+4 power rail for the CPU, then it will power up and stay up, but it won’t POST. No beeps at all and I do have an internal buzzer speaker connected to the mobo.
I have been through every test suggested by the lengthy boot-up diagnostic guide on Tom’s Hardware site. Paperclip test, many component permutations or no components at all except the CPU and PSU, multiple CMOS clearings, etc. Never helps and always the same behavior.
ASUS B250 Mining Expert
Intel Core i5 - 7th generation
2 x 8GB sticks of TForce Memory - DD4 2400
Corsair 1600i Gold PSU
Note, the above behavior occurs even if I remove every component from the motherboard except the CPU and connect only the main mobo power rail and the 4+4 CPU power rail. No post, no beeps, and if I do connect the 4+4 power rail power cycles on and off endlessly.
One thing I noticed that seems strange to me. I get why the system power does stay on if the CPU power rail is unplugged. If the CPU is unplugged, then it won’t run code that detects a problem and shut down. But for the sake of it I tried powering up with the 4+4 CPU power rail connected, but I removed the CPU completely. Despite there being no CPU, the board still powered on and off endlessly when the 4+4 CPU power rail was connected.
Why would this happen if it is code launched by the CPU is causing the quick shutdown? Or is the pipeline actually that the BIOS checks to see if the CPU is there and if it doesn’t find it, it too tries again exhibiting the same behavior but for a different reason?
I would welcome any further suggestions not covered by the diagnostic page listed above. But I think at this point I need to replace something. My fear is of course that I’ll be throwing good money after bad because the B250 never booted for me. This is not a case of a previously working system suddenly failing, it’s a system that never worked from the start.
It seems to me that I have two choices: replace the motherboard, which is way out of warranty, or the CPU. I’ve built a few systems in my life and never had an Intel CPU fail on me that I bought brand new. So should I just give up on the motherboard outright? What would be your buying strategy to fix this situation and in what order would you make your purchases to avoid wasting money on a component that is not a fault?