Bizarre PSU Behavior

[Desaan]

Corsair AX860 PSU

This started a few weeks ago with my PC failing to power on from a cold boot, motherboard LED's et al functioning but it wouldn't even attempt to POST. So after checking every single cable, reseating everything, double checking everything I could find nothing wrong whatsoever. Then in a lazy attempt to flick with PSU power switch on I kind of put it in a neutral position before if flicked back to on and the bloody PC started, past POST straight to windows, everything running fine.

So I powered it down again and attempted to start it normally, wouldn't power on until I replicated the same messing with the PSU switch as earlier. Is this symptomatic of a faulty PSU or could something else MOBO related be causing it? The entire build is less than a year old (OCUK custom built) and I don't think I've experienced an issue like this ever before. Sadly I don't have PSU of similar power/quality to test it against so I'm at a loss.

Specs
System
i7 5820k 4.0ghz
16GB Kingston Quad Channel DDR4 @2400mhz
Strix X99 Gaming Mobo
Nvidia GTX 1080 GPU
Corsair AX860 PSU
Samsung SM951 128GB M.2 PCI-e Gen3 8Gbps (OS)
Samsung 500GB 850 EVO SSD
4TB Storage Drive
Asus Xonar DX 7.1
Corsair Hydro H105 240mm CPU Cooler
Windows 10 x64 Home

 

[EsaT]

Sadly I don't have PSU of similar power/quality to test it against so I'm at a loss.

Even 500W PSU would be easily enough for testing if it boots properly without problems.

For one thing you could try clearing CMOS (or removing overclock manually) to get default clocks to see if that changes things.

 

[mattyfez]

Sounds like the PSU switch is faulty, maybe a dry solder or something.

It'll be under warranty though so I'd get in touch with customer services rather than mess with it.

 

[Desaan]

Clearing the CMOS is one of the first things I did, unfortunately after doing so and restarting it just stays in a powered off state. The PSU is modular and I don't have any spare modulars about only the 'old' kind.

It's dodgy as hell trying to turn it on but its fine once its up and running, think I'll just leave it powered on till I can sort out an RMA.

 

[pastymuncher]

Test the pc with a standard psu then. Even if you had a spare modular psu lying around you would probably blow something up if you plugged cables that were not it's own into it as different makes (and even oems within brands) use different pinouts. We have seen it happen several times on here.

 

[Desaan]

Got a replacement one today, all good now. Surprised by a Corsair PSU not even lasting 9 months.