Faulty power button or sign of something more serious?

Doctor McNinja · 30 Jun 2013 at 17:22

Sometimes when I turn my computer on, nothing happens. It's as if I haven't fully pressed the power button but after two or three presses, my computer will start. I've just tried turning it on and, again nothing happened when I pressed the power button but this time I left the computer alone as I was moving something from my (actual) desktop. After one or two seconds, the PC powered up, as if it's reaction to the power button was delayed.

Could this be a sign of something serious or is it more likely to be related to the power button itself?

NOTE: The computer was fully shut down before I pressed the power button, it was not in a low power state or any form of hibernation/sleep.

EDIT: I've just been doing a bit of research and feel it's necessary to pre-empt some questions and elaborate on what's happening as it seems that the most common problems when it comes to a delayed startup invariably involve symptoms that I do not have. After pressing the power button, nothing happens. The computer does not briefly boot only to lose power for a period of time before rebooting. Non of the fans or HDD's in my system come on. Next time I boot up, I'll use the power button on the mobo to see if the same thing happens. Although, as the issue only seems to happen intermittently (most commonly after the computer has been off since the previous day), there's no guarantee that I'll be able to reproduce the issue.

BAMBI · 30 Jun 2013 at 17:54

I would first check the power connector from case to motherboard. Is it seated correctly?

You can try shorting the power pins directly on the motherboard to turn the computer on. If it works fine every time doing this then it's the case/power button.

If not, power supply is the most likely culprit, but could also be motherboard.

Doctor McNinja · 30 Jun 2013 at 18:04

BAMBI said:
I would first check the power connector from case to motherboard. Is it seated correctly?

You can try shorting the power pins directly on the motherboard to turn the computer on. If it works fine every time doing this then it's the case/power button.

If not, power supply is the most likely culprit, but could also be motherboard.

Perhaps it is just a loose connection. I had checked the connections to the mobo but hadn't though about the other end of the wires and I was fiddling around in that area recently.

I'll check a few things when I get time but I'm gonna be a bit busy tonight.

Doctor McNinja · 30 Jun 2013 at 18:24

(Why didn't I just leave it alone so I could enjoy my Sunday night?).

I just took the top panel off to check that I hadn't knocked any of the wires when I was doing some work in that area recently and everything looked fine. I double checked the connections to the mobo and they also appear to be fine. I thought I'd take the opportunity and observe what happened when I pressed the power switch. For a brief moment I though I'd gotten lucky when I pressed the power button as nothing happened (at least I was able to replicate the problem... or so I though). Five or ten seconds and still nothing. I pressed the case button several times, tried turning the PSU off and on. I tired reinserting the PSU power lead. I tried using the power switch on the mobo itself but no matter what I do, my computer shows no signs of life other than the "POWER" and "RESET" buttons on the mobo lighting up and the lights on my GPU being on (which they are even when to computer is off).

So, I guess now the question is, can it be anything other than a PSU issue and if so, what?

Doctor McNinja · 2 Jul 2013 at 16:40

I'm just testing the PSU with a Thermaltake Dr Power II and it does pass but not always. The voltages are all within tolerances (but not as close to spec as the reviews I've read said they'd be). Where the unit occasionally fails is the PG signal. The reading is a little high at just over 500, around 530 or so but sometimes the PG test fails. I've got a sneaking suspicion that it may have been down to the way I operated the PSU tester.

With that in mind, am I right to concluded that the motherboard is the likely culprit at the moment? And, if so, how should I proceed?

Audigex · 2 Jul 2013 at 17:00

Check ALL the connections on your motherboard

My brother's PC has this issue occasionally with the GPU coming slightly loose - but it can be nearly any connection: as soon as the motherboard decides the voltages somewhere aren't right, it will simply refuse to start.

Doctor McNinja · 2 Jul 2013 at 17:12

Audigex said:
Check ALL the connections on your motherboard

My brother's PC has this issue occasionally with the GPU coming slightly loose - but it can be nearly any connection: as soon as the motherboard decides the voltages somewhere aren't right, it will simply refuse to start.

Before testing the PSU (which I took out of the case for ease), I double checked all the connections and tried to boot but again nothing happened. The lights on the GPU and mobo (which are on when the system isn't powered up) were on but nothing powered up, no fans, no HDD's. There were no signs of life at all other than the lights.

I will reinstall the PSU and check again but in the mean time, how would I go about narrowing down the fault to the mobo?

Audigex · 2 Jul 2013 at 17:22

Unfortunately it's a simple (if tedious) process of elimination. It sounds like the PSU could still be an issue, but generally an intermittent Power Good fail shouldn't consistently prevent the system from booting - although it could've blown the motherboard or RAM. Unfortunately, those parts are the hardest to test.

First up, remove everything you don't need. And I mean everything - you want to get down to the lowest denominator of hardware that can still be considered a PC.

Take out all HDDs, front USB/audio headers, any PCI/PCIe cards, any fans apart from the CPU fan, the HDD, ODD and SSD's, all but one stick of RAM. If you have onboard graphics, remove your GPU.

You basically want to end up with the CPU, PSU, front panel switch and a stick of RAM. Don't plug in a monitor, keyboard or mouse for now, just the bare minimum. Remove all PSU connectors apart from the 24 and 8 pin motherboard connections, and the GPU if it's still connected

Try to start it. If it works, add components back in, one at a time, and see if it still boots - if it does, remove that item again. If it doesn't, you've found your culprit.

If it doesn't start, swap the stick of ram out and put another in (in a different socket to earlier. If you didn't have onboard graphics, remove your GPU anyway and try again. Put it back in if that doesn't help, though. As a last check, remove your CPU fan - but again, put in back again if it doesn't help.

If none of that works, it's either your PSU, Motherboard, (all sticks of RAM), or your power switch. This is the time to try to find someone else's PC and borrow parts. First and most simply swap their front panel connector with yours and test their power switch. Then unplug their PSU from everything and connect it to your 24 pin and 4/8pin connectors (again, GPU if you left it in) and repeat the previous steps regarding RAM and GPU swapping/removal.

At this point the only possibilities are Motherboard or all your RAM, at which point swap your RAM for their if compatible, or find/buy some similar RAM (a single 2GB stick should be about the cheapest PC component you can buy). If that doesn't work, it's the motherboard.

23JMZ07 · 2 Jul 2013 at 18:08

Id be inclined to pop the PG pin out of the 24 connector block and just temporarily rig up one of the 5v lines into it's place eliminating the actual PG signal. Quite fiddly but ultimately will tell you if this PG thing is causing an issue.

Doctor McNinja · 3 Jul 2013 at 02:13

Audigex said:
*snip

Thanks for the thorough response. I'll work through a checklist when I've got time (possibly tomorrow) and report back.

23JMZ07 said:
Id be inclined to pop the PG pin out of the 24 connector block and just temporarily rig up one of the 5v lines into it's place eliminating the actual PG signal. Quite fiddly but ultimately will tell you if this PG thing is causing an issue.

That's beyond my level of expertises at the moment and I don't have to tool to remove the pins. Thanks for the response though.

Lartyconshayo · 3 Jul 2013 at 04:59

I had a similar prob. I triedcshorting the psu as per the sticky in the gen hardware section and nothing happened. Just posted it back to corsair yesterday as still under warranty.

Doctor McNinja · 10 Jul 2013 at 14:55

Audigex said:
*snip

I had some time yesterday to fiddle around and I was able to get the computer to boot with every non-essential piece of hardware removed. Again though, I'm really busy at the moment so I might not be able to start the elimination process of adding hardware for a few days.

Thanks for the checklist. It's made this whole thing a little less stressful.

farlow2012 · 10 Jul 2013 at 15:12

Audigex said:
Unfortunately it's a simple (if tedious) process of elimination. It sounds like the PSU could still be an issue, but generally an intermittent Power Good fail shouldn't consistently prevent the system from booting - although it could've blown the motherboard or RAM. Unfortunately, those parts are the hardest to test.

First up, remove everything you don't need. And I mean everything - you want to get down to the lowest denominator of hardware that can still be considered a PC.

Take out all HDDs, front USB/audio headers, any PCI/PCIe cards, any fans apart from the CPU fan, the HDD, ODD and SSD's, all but one stick of RAM. If you have onboard graphics, remove your GPU.

You basically want to end up with the CPU, PSU, front panel switch and a stick of RAM. Don't plug in a monitor, keyboard or mouse for now, just the bare minimum. Remove all PSU connectors apart from the 24 and 8 pin motherboard connections, and the GPU if it's still connected

Try to start it. If it works, add components back in, one at a time, and see if it still boots - if it does, remove that item again. If it doesn't, you've found your culprit.

If it doesn't start, swap the stick of ram out and put another in (in a different socket to earlier. If you didn't have onboard graphics, remove your GPU anyway and try again. Put it back in if that doesn't help, though. As a last check, remove your CPU fan - but again, put in back again if it doesn't help.

If none of that works, it's either your PSU, Motherboard, (all sticks of RAM), or your power switch. This is the time to try to find someone else's PC and borrow parts. First and most simply swap their front panel connector with yours and test their power switch. Then unplug their PSU from everything and connect it to your 24 pin and 4/8pin connectors (again, GPU if you left it in) and repeat the previous steps regarding RAM and GPU swapping/removal.

At this point the only possibilities are Motherboard or all your RAM, at which point swap your RAM for their if compatible, or find/buy some similar RAM (a single 2GB stick should be about the cheapest PC component you can buy). If that doesn't work, it's the motherboard.

definatly best way to eliminate everything else but id say psu

Rainagul · 10 Jul 2013 at 15:20

My money is on the motherboard has gone, had similar symptoms happen to me a while ago. That said, check the PSU first.

Doctor McNinja · 15 Aug 2013 at 01:53

First it's the weather, then it's visiting relatives, then it's work...

I've finally got around to trouble shooting the problem.. well, I say trouble shooting. I decided to take the opportunity of upgrading my case to a 900D (relevant gif below) and after taking everything apart (including removing the CMOS battery), everything seems to be working. I'm guessing I've just learned a CMOS related lesson.... anyway, thanks for the help everyone.

http://latimesblogs.latimes.com/.a/6a00d8341c630a53ef015391422b9f970b-600wi