Weird problem not powering

thedoc46

thedoc46

thedoc46

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Mobo is Asus P8Z77 LX Pro, PSU is Cosrair AX750.

Anyway, machine has been running fine, being powered on and off at least once or twice a day.

However if i accidently press the power button on the case and force a shutdown, via the power button on the case, the machine will NOT power back up. and i mean nothing.. no start of fans or beep, just as if the power cord is out... Regardless of what i do. Even pulling the cord. It's happened once or twice before, and i've been lucky enough to bring it back to life, by unplugging everything, leaving it off for a few mins, plugging everything back in, and it started working fine again. powered on by the button on the case, and powered off via the Windows power off.

Anyway, today i accidently lent my foot on the case, and pressed the damn case power button again.. so the machine shut down... I've tried EVERYTHING this time though to get the machine to fire back up.

Going as far as unplugging everything including the GPU, and even removed the mobo cmos battery... AND it did actually fire up... but when i shut it down, the power button on the case failed to power up the pc, unlike it has done in the past, once i've managed to get it working by pulling everything out and going thru the hassle of plugging it all back in.

It can't be a loose connection cos its been worknig forever, and something happens when that case button gets pressed that it must put the machine in some weird kind of hybernation that's impossible to bring out of..

I've reset the pins, unplugged all the cords, cards and i'm just not getting this thing to work this time round, even changed the cmos battery.

arrrggghhhhhh

i hate to say i have a faulty mobo, cos it works flawlessly unless that damn case power button is pressed.

Anyway, lost for idea's. Rather not buy a new mobo to find out its something else, i just don't understand why this problem only emerges when the case power button is used to shut the machine down.
 
Last edited:
wazza300 said:
Leave it for a few hours unplugged and CMOS battery out,then try
Click to expand...

What use is that going to do ? Honest question

If i've already taken out the cmos and left it for a few mins... vs a few hrs...

how does it store with absolutely no power.

I'm thinking i've just got a faulty board being held together by a piece of string somewhere... I'm going to be a refurb one for $55. Which isn't that bad...

Got to go with the gut on this one....
 
I've managed to get it going again. sorta.... updated the bios to the latest version, and managed to get into Windows and changed the power profile so that if i press the power button it does NOTHING

But i'm still in testing.. As a couple of times i've pressed the power button to turn on (after a windows shutdown) and it didn't fire up... So had to clear the cmos again... (which again didn't work one time, but did others)

So something is still amiss. Don't know if its my mobo, psu or something else sinister going on. Not ruling out the power button on the case, but i'd say thats the most unlikely thing it is, just by the very nature of it working all the time (up until today), APART from the time i pressed it to power down the machine..
 
The thing to do is check whether the motherboard exhibits the same behaviour when started by shorting the power button pins on the motherboard (the pins that connect the case button to the board). If so, dodgy motherboard or less likely, dodgy power supply. It'll be one or the other.
 
nah, still not working... thought i had it, cos it worked a few times, but the power button again is doing nothing, not even clearing the cmos is helping at the moment.. Running everything on default in the bios. :(
 
Trying to short the PWRSW pins using a screwdriver, and still nothing.... i guess i do have my kids pc, with an AX650 instead of an AX750 psu, i could whip out and divide and conquer to make sure its not the PSU.

They're both modular so i think i'll give this a go.
 
Confirmed.... its a faulty PSU Corsair AX750.... 7 yr warranty apparently. But i'm sure they take weeks to get you a replacement..

Trying to cancel the mobo i ordered. Again hard to do on a Sunday. Hopefully they get the memo, before shipping tomorrow.

Damn psu, has had me running around chasing my own tail all damn day !

At least i now know what it is...
 
ExRayTed said:
Good result. Never buy Corsair PSUs any more
Click to expand...

:D i've just bought the new AX760i to replace this and it'll be here tomorrow, cos the RMA is going to take a few days (in other words way too long)... Oh well, I'm building my other kid a pc for Christmas, so he can have my RMA AX750 when they get around to replacing it...
 
thedoc46 said:
:D i've just bought the new AX760i to replace this and it'll be here tomorrow, cos the RMA is going to take a few days (in other words way too long)... Oh well, I'm building my other kid a pc for Christmas, so he can have my RMA AX750 when they get around to replacing it...
Click to expand...

Sorry to hear about your AX750. Glad to hear that you took advantage of your 7 year warranty.

Perhaps I can help speed up your RMA process. Post your ticket # here and I'll look into myself ;)
 
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