After shutdown, computer won't boot unless PSU shut down

[spike-It]

I upgraded my machine toward the end of this summer. Put in a new motherboard, memory and installed the OS on an SSD. I kept my video card, enclosure, HDDs, and my old power supply. For the first month or so the system was solid. It passed every stability test I threw at it.

After that period of time, I noticed the machine having issues coming out of hibernate. It would hibernate, but would restart. I'd have to power the machine back up and it would recover the hibernate state. Eventually I adjusted Windows to never hibernate. All was well.

A few weeks later the machine would not power up after a shutdown. Shut the machine down, walk away, come back a bit later, hit the power button -no dice. Would not start.

I can get it to power up. To do so, I have to shut down my power supply. Then turn it back on and let it sit for 5 minutes or so ( I haven't timed this precisely ). After doing this, the machine powers back up fine. Once the machine is running, its runs stable as can be. No power issues whatsoever.

So, am I looking at a motherboard or a powersupply issue? I don't have a spare power supply sitting around. I've been meaning to track one down so I can swap my old one out and see if that's the problem. I'm suspecting its the motherboard which seems like a painful experience to pursue with the vendor. I have not tried to OC with this MB yet.

Any thoughts?

Specs:
ASRock Z68 Extreme4
Intel Core i5 2500
Kingston 4Gx2 KHX1600
Crucial M4 128GB SSD
Sony Optiarc DVD Burner
Seasonic SuperTornado SS400FB 400W
Plus a few harddrives

 

[KGB]

Try clearing the CMOS per the MB manual.

 

[discerning]

I think it's your PSU. 2A on the standby rail is insufficient for ATX12V 2.2 (minimum 2.5A). A workaround is if you have USB devices plugged in, try removing them.

 

[spike-It]

Try clearing the CMOS per the MB manual.

Tried that, it didn't make a difference.

 

[spike-It]

I think it's your PSU. 2A on the standby rail is insufficient for ATX12V 2.2 (minimum 2.5A). A workaround is if you have USB devices plugged in, try removing them.

Interesting. I've never really looked into the standby rail. Maybe this is it. However this doesn't explain why it worked fine for the first month or so. Nothing changed has changed in my configuration since the initial build. I tried removing what I had for USB devices (not much), and I even unplugged a couple drives, but this didn't make a difference. What devices draw off the standby rail for the boot?

 

[Kenmitch]

Interesting. I've never really looked into the standby rail. Maybe this is it. However this doesn't explain why it worked fine for the first month or so. Nothing changed has changed in my configuration since the initial build. I tried removing what I had for USB devices (not much), and I even unplugged a couple drives, but this didn't make a difference. What devices draw off the standby rail for the boot?

Power output from a power supply can slowly degrade with time. The power supply may have been overshooting the voltage just enough to work the first month or so. It's possible this is your problem but is also possible it's not even related. Just one of those could be things as yours isn't up to spec.

 

[jsalpha2]

I had something similar after trying a linux live CD. Had to unplug, then hold the power button in for a few seconds,fans spin for a second, plug back in, then would start. Never figured out why.

 

[spike-It]

Thanks to everyone for the help here. I finally got hold of a more modern PSU, installed it and now everything works great. Shutdowns and restarts are fine. Hibernation works perfectly.

I can't complain. My old PSU was almost 8 years old and quite frankly still (quietly) humming along. I guess a bit of degradation over the years in parallel with standards updates did it in. I'd rather it went that way then with a loud pop.

 

[BadThad]

Yep, power supplies slowly degrade.....glad you fixed your problem and I'm also glad you came back to share your results. It might help someone else another day.

 

[Nathaniel77]

In my situation, the computer would not start after shut down. Every time I had to turn off the power with 0 button on the power supply. And you won't believe what was causing the problem. Display Port from the graphics card. When I plugged in HDMI cable from the graphics card to monitor, all was working well. The issue never happened. Then I unplugged it, and I plugged in Display port cable from the graphic card to display port in the monitor, and baam. The issue happens again (after shut down it won't start).

Display port from graphics card GTX 1070to display port in the monitor was causing the problem. Why? I don't know. My guess is that display port cable tries to take more power from the power supply, and power supply tells, well you won't sir, and shuts down.

Ok, people, connect HDMI cable from your graphics card to HDMI in your monitor. Or if you don't have HDMI, try with a simple VGA port connection to VGA in a monitor.

Hope this will save some of you from headaches.

Regards

 

[VirtualLarry]

cheap displayport cables send +5v on pin 19 or is it 20. You need a proper vesa-spec cable that doesn't pass power on that pin. Look up "accell" cables on Amazon.