Power to P8Z68-V Pro Gen3 but System won't Turn On

Last night I went to restart my PC and just after the BIOS screen the system just shut down. Now I can't get it to power on at all. This system has been running great for about 4 months since I built it.

I do have power getting to the motherboard. The Power and Reset buttons on the edge of the mobo are lit but don't do anything when I press them. The power on button and reset button on the front of the case don't do anything either. I have tried reseating all 4 DIMMs, disconnecting and reconnecting all power connectors. Even tried swapping the connectors for Power and Reset to see if I could get the Reset button to power the system up... thinking maybe the Power Button just quit working. Of course that didn't work.

If it just shut down during a reboot I'm afraid that means something fried but I don't know where to start.

Can someone give me some ideas please?

System:
Asus P868-V Pro Gen3 mobo
4 x G.Skill RipJaws 8Gb DDR3-1600 PC3-12800 DIMMs
Corsair HX-850w PSU
Thor V2 Full Tower Case
Intel Core i7-2600 CPU
2 x Sapphire Radeon HD 6970 2Gb Video Cards

I don't think the rest matters much but I have a 120Gb SSD boot drive and two 2Tb HDs, Blu-Ray burner and DVD-ROM drive.

Would greatly appreciate some guidance here. I rely on my PC for my income!
14 answers Last reply
More about power p8z68 gen3 system turn
  1. Quick update... I tried removing both of my video cards and disconnecting the power from them both. Also tried removing 3 out of 4 of the DIMMs. Then replaced the one installed with a different one.

    So far nothing. System will not power up. No fans move. But power and reset buttons are lit up on mobo.
  2. sound like you lost a leg on your power supply. you may be getting the 5v leg witch would power on the on/off part of a mb but you might be missing the 12v rail. with no ram or video if the mb and cpu have power you should have gotten some fan spin and a beep code. if you have meter you can take the ps out and do a green wire test to see if it come on and have the right voltages. hopfull when the ps died it did not take anything with it.
  3. I do have a meter but I don't know what a green wire test is. Can you explain that to me?
  4. I have an ASUS Z68-V mobo and something similar happened to me. Try with a different power supply, that was my problem. I had a corsair tx650 V2 wich worked fine for about one month and then one day my computer just switched off when i was using it. The mobo power led (near the usb headers) turned on but the system wouldn't start up, tried with a different psu and it booted fine. The corsair psu died with no warnings...
  5. javier_machuk said:
    I have an ASUS Z68-V mobo and something similar happened to me. Try with a different power supply, that was my problem. I had a corsair tx650 V2 wich worked fine for about one month and then one day my computer just switched off when i was using it. The mobo power led (near the usb headers) turned on but the system wouldn't start up, tried with a different psu and it booted fine. The corsair psu died with no warnings...


    After that last reply I was wondering if the PSU could be the problem. Now after your reply I have to assume it is. Seems very unusual to me to have a Corsair power supply go bad at all, much less after a few months of working fine. They are such good quality. Under warranty too, I think. Bought it from Newegg.

    I do have a media server upstairs that I built over a year ago and put a smaller Corsair PSU in that one. I think I'll pull that one off the rack and swap out the power supplies tonight to see if that does the trick. If so, I guess I have no media server for a while.

    Did you get yours replaced under warranty? If so, how long did it take from the time you shipped yours back?
  6. pickupcash said:
    After that last reply I was wondering if the PSU could be the problem. Now after your reply I have to assume it is. Seems very unusual to me to have a Corsair power supply go bad at all, much less after a few months of working fine. They are such good quality. Under warranty too, I think. Bought it from Newegg.

    I do have a media server upstairs that I built over a year ago and put a smaller Corsair PSU in that one. I think I'll pull that one off the rack and swap out the power supplies tonight to see if that does the trick. If so, I guess I have no media server for a while.

    Did you get yours replaced under warranty? If so, how long did it take from the time you shipped yours back?


    Unfortunately i live in Paraguay southamerica, and if i want to use the warranty i have to ship it back to USA again, the shipping cost would be to high to make all the hazzle worth it... so that was 100+ $ that went to the trash. The green wire test that someone mentioned (first completely unmount the psu from your computer for safety) involves making a bridge in the ATX 24 pin conector between the ONLY green wire in that connector and any of the black wires(GND) this should trigger the PSU on, and using a voltimeter you could check the outputs of your psu. If by doing this your psu doesn't turn on, it's probably dead... you could google for more information, there are some nice graphics tutorials around...
  7. Well, as much of a pain as that was... it did not help a bit. I swapped out the power supplies with a known good one (Corsair HX-750) and nothing changed. Power and Reset buttons are lit up on the mobo but the system will not power up. No fan movement at all.

    What else could it be? It's probably not the case power switch, right? Wouldn't that just leave the motherboard?
  8. Maybe I don't understand this correctly but something bothers me about this. There are 4 case fans. Each fan plugs into a connector that is wired to the front panel fan speed controls. 2 fans per control. Then there is a single pair of power wires, red and black, that connects to the power supply.

    If the case fans are not coming on then it can't be the motherboard, right? It would have to be the power supply or the front panel wiring or something on the case there that's not working right. I have already eliminated the power supply by using a known good one.

    Am I correct here or am I missing something? And is there a way to just bypass the front panel somehow, temporarily, just to see if that is the problem?

    Again, it's a Thor V2 full tower case, purchased from Newegg.
  9. pickupcash said:
    Maybe I don't understand this correctly but something bothers me about this. There are 4 case fans. Each fan plugs into a connector that is wired to the front panel fan speed controls. 2 fans per control. Then there is a single pair of power wires, red and black, that connects to the power supply.

    If the case fans are not coming on then it can't be the motherboard, right? It would have to be the power supply or the front panel wiring or something on the case there that's not working right. I have already eliminated the power supply by using a known good one.

    Am I correct here or am I missing something? And is there a way to just bypass the front panel somehow, temporarily, just to see if that is the problem?

    Again, it's a Thor V2 full tower case, purchased from Newegg.


    The mobo needs to send a signal to the psu for it to turn on, thats what you are doing with the green wire test... forcing the psu to turn on. So if the mobo doesn't send the signal to the psu to turn on, the case fan won't spin either.

    Another thing that you could check is that the mobo isn't making short with the case somewhere, check that the mobo standoff are properly installed and that there aren't any "extra" standoff in place(where the mobo doesn't have a hole for a screw), that could also cause the problem.

    I don't know your particular mobo but mine have a power button next to the internal usb headers.. it accomplishes the same function of the case power switch (so you can rule that out). That's about everything that occurs to me you could try... sorry we couldn't help you!
  10. javier_machuk said:
    The mobo needs to send a signal to the psu for it to turn on, thats what you are doing with the green wire test... forcing the psu to turn on. So if the mobo doesn't send the signal to the psu to turn on, the case fan won't spin either.

    Another thing that you could check is that the mobo isn't making short with the case somewhere, check that the mobo standoff are properly installed and that there aren't any "extra" standoff in place(where the mobo doesn't have a hole for a screw), that could also cause the problem.

    I don't know your particular mobo but mine have a power button next to the internal usb headers.. it accomplishes the same function of the case power switch (so you can rule that out). That's about everything that occurs to me you could try... sorry we couldn't help you!


    Javier,

    You have been trying to help and you are giving me good information and suggestions. That's all I want.

    Ok, so would you agree that since I tried a known good power supply (had to shut the system down so it was up and running with no problems) and that didn't change anything, that I can now rule out the power supply and there is no need to do the green wire test?

    Second, if the mobo is supposed to send a signal to the psu to turn on, apparently it isn't doing that. The power button on the mobo is lit up but doesn't do anything and I have also tried using the case reset switch like a power button just to rule out the case power button. I doubt both the reset and power buttons would go out at the same time.

    So, based on this information I would hazard a guess that the motherboard is fried. Would you or anyone else like to agree or disagree? I need to get this system back up fast and if it's the motherboard the only thing I can do is order a new one because I don't have another i7 motherboard to use. I could do it with a warranty replacement but that would slow things down a lot I think.

    I just want to be a sure as I can that I'm ordering the right thing. I can't afford to wait a few days and then find out it wasn't the part I just ordered.
  11. Quick update: Just did the green wire test on the psu I removed earlier. The power supply does turn on and the psu fan spins. When it is in the pc and connected to the motherboard it does not turn on and the fan never spins.

    So again, I think I have to assume that the power supply is good and for whatever reason the motherboard is not sending the turn-on signal to the psu or the other case fans and is more than likely fried.

    Would anyone care to agree or disagree? This Asus mobo was like $259. Not a cheap one.
  12. It could very well be the mobo for what you are saying.. When the problem is the memory or processor or something like that, generally the mobo emits error beeps.. If nothing like that happen my best guest would be a bad mobo, since the processor rarely fails and the mobo doesn't emit error beeps to make me think is the memory.

    Something similar happened to a friend of mine.. It was because the mobo was making short with the case at some point.. The power button lid but the system wouldn't turn on.. I removed the mobo from the case, to my surprise it booted fine off the case. I think that is the last thing you could try..
  13. javier_machuk said:
    It could very well be the mobo for what you are saying.. When the problem is the memory or processor or something like that, generally the mobo emits error beeps.. If nothing like that happen my best guest would be a bad mobo, since the processor rarely fails and the mobo doesn't emit error beeps to make me think is the memory.

    Something similar happened to a friend of mine.. It was because the mobo was making short with the case at some point.. The power button lid but the system wouldn't turn on.. I removed the mobo from the case, to my surprise it booted fine off the case. I think that is the last thing you could try..


    I was pretty confident it wasn't the motherboard shorting on the case somewhere. For one thing, the system was running fine for 4 months.

    Anyway, new ASRock mobo came in yesterday evening. Just finished installing it and that was in fact the problem. Have contacted Asus about an RMA. I ordered a replacement mobo because Asus says it can take up to 30 days to get a replacement in and I can't wait that long. Need my system to make money!

    Thanks again for your help, Javier. I really appreciate it.
  14. Sorry to hear you had to return yours, haven't had any issues with mine (knocking on wood as I type this).
Ask a new question

Read More

Asus Power Shutdown Motherboards