ASUS Z87 - Blinking "FLBK_LED" light

[n00neimp0rtant]

Hello, I'm brand new here. I just finished my first DIY PC build, and found this forum while looking for support. Seems like a friendly and helpful place to get advice and chat about PC stuff.

My first build is using an ASUS Z87 GRYPHON mobo; every part (including the mobo) is completely new, sealed in box. When I finally got everything put together, I plugged it in, turned on the PSU, and 2 lights lit up on the mobo: a big, round, green one that stayed on solid, and small green one labeled "FLBK_LED" that blinked on and off about every second or so. When I press the power button on the case, absolutely nothing happens; no fans, no additional lights...nothing.

Looking for support, I found a number of a terrifying suggestions: PSU could be bad, mobo could be bad, or something could be shorting out the mobo. I did see a few people with the same issue saying that their machines would turn on if the power button is held while the PSU is switched on. I tried that, and wouldn't you know it—it turned on. It then shut off after about 5 seconds. So I tried it again, and it stayed on this time. Moved the machine over to my monitor, plugged it in, tried again, and it turned off after 5 seconds. I've tried this about 20 times now, with a solid 50% success rate. Half the time, it just turns off after 5 seconds; the other half, it stays on.

And it's a good "on" too. I was able to get into the BIOS, configure my boot devices, and even fully install a copy of Windows 8 on the machine. And once it's on and booted up, I'm not experiencing any sudden shut offs or anything rogue like that. But the issues have not gone away. If I turn on the PSU without holding down the power button, I still get the blinking FLBK_LED. And if I hold down the power button while turning on the PSU, I still have that ~50% chance that the machine will shut back off after 5 seconds.

Obligatory reminder that I'm completely new to this, but I have a hard time convincing myself that any of the parts could be bad. They are all brand new, and once the machine gets booted up, I have no problems at all. But I just can't fathom what could possibly be causing this issue. I'm aware that the FLBK_LED is only supposed to blink while the mobo is awaiting a BIOS flashback, but I can get into the BIOS if I interrupt a successful boot with the delete key, and everything in there seems to be in order. Just trying to fish for some suggestions on what might be wrong and how I might be able to fix it.

Thanks in advance.


Part list:

 

[ATMINSIDE]

Can you provide a full listing of the parts in this build, including model numbers?
In this please include the BIOS version on the motherboard.

 

[n00neimp0rtant]

Absolutely, just edited the first post with the parts. Unfortunately, I'm at work right now so I can't get the BIOS version. If I'm still unable to get it fixed tonight, I'll post it. Thanks so much for the speedy reply.

Also, I'm aware the PSU is overkill for the rest of the build, but I want to leave room to upgrade aggressively, so I didn't want to be bottlenecked by PSU wattage.

 

[ATMINSIDE]

Looks like it isn't a part incompatibility.

I would check for shorts.
Make sure the polarities on all the case wire connections are correct, I've seen the HDD Activity LED and little things like that cause issues like this before.

 

[n00neimp0rtant]

Yikes. I'll definitely check all of those again.

If that doesn't fix the problem, is it at all possible that the case is causing the short? It's mounted directly onto it, and it's all metal. Would it be a bad idea to remount it with a very thin sheet of plastic or packing foam between the case and the board?

Also, if the problem does turn out to be a short, could I have been doing damage to any of the parts by "forcing" it on with the PSU switch method I described?

 

[ATMINSIDE]

Did you use the standoffs when attaching the motherboard to the case?

By holding the power button? No, that won't hurt anything.

 

[n00neimp0rtant]

Oh these things?



You know, I was wondering what those were for, and why there were so many "screws" left after I finished the build.

Going to remount the mobo using the standoffs this time. I expect it to fix the problem, but I'll report back if it doesn't. Thanks so much for the tip.

 

[ATMINSIDE]

Yes, those. They go between the case and motherboard.

There's the issue with the FLBK_LED though.

 

[Nebulous]

Lucky the board didn't go POOF!