Won't power on unless.....

dlads

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Sep 24, 2010
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Hi there,

Have been building PC's for quite some time now and i've got a fair old beast now, however when i power on the PC, i have to jiggle the power switch on the PSU.

Here's what happens.

PC is cold, power from the wall, switch on PSU is set to on.

1. Switch on PC from the power button on the case, PC boots but nothing on screen, keyboards don't light up but everything on the inside do not.

2. The motherboard also doesn't completely light up, there is a counter which i'm assuming is some kind of through check for the motherboard and attached components doesn't come on.

3. The PC will sit in this state forever and won't progress to windows.

*Other times i perform the same steps but instead the fan on the GPU will go to max and will stay there with the above symptoms, forcing a power off from the PSU switch and pulling the power, then allowing the systems lights to all dim out (essentially removing all power and surges from the PC)

To remedy this here's what i do.

Again PC is cold.

1. Power on the PC from the case button.

2. Quickly before it boots to what would be the bios, I switch the PSU switch off and then on again.

3. When i do this, the red light on the motherboard cycles and then the counter starts to go up.

The keyboards light up, the monitor recognises a PC is attached and the PC boots as normal and is usable for as long as I need it.

I've bought another PSU from amazon (DPD failed to try to deliver and then lied, avoid them)

This is the PSU i've got coming.

https://www.amazon.co.uk/gp/product/B01BGG5PTM/ref=oh_aui_detailpage_o01_s00?ie=UTF8&psc=1

The PSU i have at the moment is the Corsair GS800 (800watt PSU)

I haven't overclocked anything at the moment, all components come back after a diagnosis as clear and i have no errors, BSOD's or anything similar.

Has anyone heard of this? Seen it or fixed this issue? I'm just a bit puzzled and if it turns out to be the motherboard i'll be gutted after buying a PSU.

Any help would be appreciated, as i'd like to put the PSU into a second PC.

Up to date specs:

Antec 900 (no extra fans, all in working order)
i5 4670K @ 3.4GHz (stock)
Z97 AsRock Extreme 4 motherboard
16GB DDR3 Corsair Vengeance RAM
EVGA GTX 1080 GPU (stock)
Corsair GS 800 PSU
 
Solution
What hard drive? Spinning or SSD ? (Fiddling the PSU switch might change the spinup on a spinning hard drive).

What BIOS code is reported, if any, when you do a normal power up ? The counter you mention is the BIOS reported POST fail code. The MB manual will tell you what the code means if you get a code.

Normal debugging is to remove parts until the PC starts cleanly with the PC power button or reports the proper error. For example, pull the video card. If the PC still does the same hang then the video card is likely not the problem. If the PC instead starts to boot and gives you a POST error code that says "no video" then suspect the video card.

This could be the PSU, hope for you it is. If not the PSU suggest you debug by...
What hard drive? Spinning or SSD ? (Fiddling the PSU switch might change the spinup on a spinning hard drive).

What BIOS code is reported, if any, when you do a normal power up ? The counter you mention is the BIOS reported POST fail code. The MB manual will tell you what the code means if you get a code.

Normal debugging is to remove parts until the PC starts cleanly with the PC power button or reports the proper error. For example, pull the video card. If the PC still does the same hang then the video card is likely not the problem. If the PC instead starts to boot and gives you a POST error code that says "no video" then suspect the video card.

This could be the PSU, hope for you it is. If not the PSU suggest you debug by
1.removing all hard drives cables, see if you get a "no boot device message" if so suspect the cables or the hard drive. (If you get the same hang and no message then it's likely not the disk).
2.with the hard drives still not connected remove the video card. as above, a "no video" post code means the video card is suspect. A hang means its likely not the video card.
3.remove the ram. If you see a "no memory" post code then add back the stick one at a time.
4. if you get the same hang with no memory or any other parts on the MB except the CPU and CPU fan, then its the MB, PSU or CPU. You've already planned to swap in a PSU, next would be MB. It's rarely the CPU.

Note: often physically removing and re-inserting the failing part can fix it (for eample, if there is some dirt/corrosion in the connection.) If you find the PC POSTs when you've pulled a part put it back in and see if the PC continues to POST normally. This is not uncommon.

Good luck. Also there is a good sticky that links more procedures to debug a PC in your state. Also google "breadboarding"


UPDATE: Aside, i would get the BIOS updated and then RESET to defaults before I did too much more work (assuming the new PSU does not fix the problem).
 
Solution

dlads

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The hard drive for windows is an ssd, i have three other drives all spinning.

I've taken down the components and the symptom remains, i've recently changed my GPU from an r9 290 tri-x which also showed the same problem.

Also when the system boots up with the error, the mobo doesn't show a code at all, there are no lights around the code area, only when i flick the power on boot will it light up red and boot, the code is normal and not an error.

Really weird.
 

dlads

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I'll pop it in the other PC when the new one arrives and see if it exhibits the same issue, then i suppose i'll know.

Appreciate your response there too, i wasn't aware their warranty length :)
 

dlads

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Just to update you guys, the problem has gone from my PC and the new power supply, EVGA 850w gold G2 has allowed the motherboard to post everytime.

Popped the other PSU into my other PC and tried the off on trick, didn't post once, tried the old PSU and it's now back in business, only two years old so i'll RMA it.

Thanks for your answers.