Asus X99-A Suddenly Won't POST, Q-Code Blank

Tetsujin · 19 Mar 2016 at 13:09

Hello! I built a new system last May (Asus X99-A mobo, i7 5820K cpu, Be Quiet DPP P10 850W psu, 2x MSI 970 gpu in SLI, 32GB Corsair 2400 ra, Samsung 850 Pro ssd) and it's been working perfectly fine since then, until last night.

I rebooted it at 2am, and after power-down it didn't come back up. Tried the case power button, nothing. Case reset button, nothing. Opened up the case and the mobo's red PWR_SW led is lit, the green RST_SW next to it is also lit, but nothing on the Q-LED, and nothing else lit. No fans spinning (save for one in the PSU, I think), no power light on the GPUs, but my mouse and backlit keyboard do light up, as does my external USB soundcard. So I know power's going to the mobo and out the USB in general, but with no Q-CODE I can't see where it's hanging. Tried the on-mobo power and reset buttons too, also nothing.

I normally keep it on 24/7, CPU's had a 4.3GHz OC since initial build with a 1.175v overvolt too. OC'd the GPUs too slightly. If I'd fried either of these I'd expect to see something on the Q-LED though. Sometimes when I've been powering the PSU on/off this morning the Q-LED has briefly lit up (only for the briefest instant whilst turning off, never as part of the POST process), so I think in general the LEDs themselves there are working.

Anyone any ideas where to start? I fancy it's either the mobo or the PSU that's messed up, but in ~15 years of building machines I've never had an issue with no indicators before so I'm not sure where to start.

The machine's currently out of its under-desk home, case open ready to be tinkered with, but I'm not sure where to tinker. I've removed extraneous USB devices and still see no joy, only the two aforementioned LEDs lit, nowt else.

Thanks for reading!

ExRayTed · 19 Mar 2016 at 13:20

Reset the CMOS and try again

Tetsujin · 19 Mar 2016 at 13:33

Thanks - just tried this, which also entailed taking the second 970 out to get to the jumper; still no joy, same result. Going to try removing the CMOS battery method next too, though.

Have also noticed that the PSU fan isn't actually spinning. There's coil whine from it, but the fan stays off - it being a "Be Quiet" one, I'm not sure if this is a sign of a problem or normal behaviour, though.

Tetsujin · 19 Mar 2016 at 13:39

Have used battery removal method for CMOS clearing, still no change. Noticed also that the occasional flash of the Q-LED I mentioned seems to happen when powering off the PSU if it's been sat there on for a while. Some of the system fans also start to slightly rotate in the same instant as the power switch is flicking off, as though the act of switching the PSU off is causing a brief flicker of power to go around the system. Strange?

Alz_D · 19 Mar 2016 at 13:40

Do you have a spare PSU to try?

Tetsujin · 19 Mar 2016 at 13:43

Alz_D said:
Do you have a spare PSU to try?

Only other PSU I have is in my old P5b Deluxe/Core 2 Duo system from about ten years ago, don't think it'll even have the right power connectors for a modern mobo.

Are there any devices I could get, from somewhere like say Maplin, for testing PSUs in any way?

Tetsujin · 19 Mar 2016 at 14:45

Also noticed that the PSU's "overclocking key" light doesn't come on whether it's turned on or off. This is some thing which switches the PSU from single- to multi-rail mode, I believe. So if its own indicator light isn't firing up, I guess that indicates a fault there?

I've also seen the mobo's Q-LED light up and start cycling through codes when I held the PSU's on/off switch in a halfway position.

Tetsujin · 19 Mar 2016 at 20:00

Well waddyaknow - turns out my PSU did fit with my 10 year old rig, exact same power specs from the mobo manuals. And, it did the same thing, sat there with juice to mobo power leds but wouldn't actually boot. Slapped the original PSU back in the old rig again, and it fired up good as ever.

Looks like it's the PSU. Better to arrange returns with the retailer or the manufacturer, in general?

Alz_D · 20 Mar 2016 at 11:00

Depends on the brans of PSU - if it was from here ask in the CS section - double check all your connections as well to make sure its not a loose one somewhere. Glad you've found the culprit anyhow

Tetsujin · 21 Mar 2016 at 19:47

Sadly it was mildly cheaper at a competitor, who the cryptic clue for is that their name might be involved in the consumption of barcodes, so here's hoping their support's decent. It's 24 hours since I contacted them about it and no response yet though so... mehh

Rensin · 21 Mar 2016 at 20:42

Tetsujin said:
Sadly it was mildly cheaper at a competitor, who the cryptic clue for is that their name might be involved in the consumption of barcodes, so here's hoping their support's decent. It's 24 hours since I contacted them about it and no response yet though so... mehh

I wouldn'nt build your hopes up too much.

I bought something from them listed as Grade A condition, item arrived and looked like a little kid had messed around with it for a few months, the scratches/dings had been coloured in with permanent marker, connectors were broken ect.

CS accepted the return (after several emails) item was returned and promised the return cost & original delivery cost refunded (£20) in which I am still waiting for after several emails, calls.