P8Z68 - MOBO Problem???

Thank you for your time.
I have searched all over the net and TH trying to find a solution to this problem, but I haven't found much...
A few similar "restart issues:"

I just put together my first build:
Asus P8z68-V Pro
i7 2600k
Noctua Heatsink
GTX 570

Everything went well, and I was able to boot and install win 7 x64 without a problem. I was so happy :ange:
But soon I noticed that whenever I tried to boot the computer, it would start, turn it self off after a few seconds, and then finally boot normally.

I thought this was weird, but some research on the net convinced me that maybe it was normal, part of ASUS auto-tune/auto-OC.

But from there, things just went downhill: When I try to start my computer now, 4/5 times, the CPU led stays on, no POST, no BEEPs, nothing.
I usually, unplug the power, wait, and try again. After a few tries, I usually manage to get the computer to boot, and I can get windows up and everything seems fine. (this leads me to think that CPU, memory, and Graphics card is fine)

Here is what I have tried:
-Removed Graphics card, no changes
-Cleared CMOS, remove battery, and reset bios to default.
-Updated bios from 0501, to 0601 (this was my biggest hope - nothing changed) :(
-Set AI Auto-tune to manual, in the OS and Bios

I would really appreciate any suggestions you might have.
Bad MB? Bad CPU? Bad Settings? Bad Bios?
9 answers Last reply Best Answer
More about p8z68 mobo problem
  1. UPDATE:

    Other things I have recently tried.
    -Single RAM stick
    -Re-seating CPU

    I am thinking of RMA-ing the board tomorrow, unless someone has any reason to believe it could be something else....?!
  2. gtalarico said:

    But from there, things just went downhill: When I try to start my computer now, 4/5 times, the CPU led stays on, no POST, no BEEPs, nothing.
    I usually, unplug the power, wait, and try again. After a few tries, I usually manage to get the computer to boot, and I can get windows up and everything seems fine. (this leads me to think that CPU, memory, and Graphics card is fine)

    PSU. What kind? Symptoms indicate a possible PSU problem.
  3. Antec EarthWatts 750.

    What really confuses me, is last night for example, once I finally got it to boot,
    everything was running smooth, I installed a bunch o programs, and even rendered a 3d scene for about 20 minutes.

    I am going to RMA the MB today, should I also return the PSU?
    Is there any way to test whether the PSU is really problematic?
  4. Ok, I have been talking to Raja, from Asus.
    He suggested that I try a single DRAM module... same problem... CPU light is on...

    How do I know if it is the MB, cpu, or psu?
    (remember that whenever I am actually able to boot it, everything runs smooth, even 3d rendering - this tells me cpu is ok...?)

    I need to figure this out soon so I RMA it to new egg : (
    Should I rma all 3 just in case?
  5. Please....?
  6. ASUS finally wrote me back and suggested that I send the board back due to "inconsistent posting".
    I have the mb boxed and I am going to mail it tomorrow, but I get a feelling it is not an issue with this particular board, but with the model, or the bios, not playing nice with something else (memory?psu?)
    Although it worked fine with single module....

    I am lost and kind of starting to regret ever getting into this... : (
    Any insights would be greatly appreciated.
    Many thanks.
  7. Best answer
    I have been away from my computer for awhile.

    The only way that you can verify any of those components is to substitute known good parts.

    Now, it is very unlikely that the CPU is the problem. The Asus Z68 motherboard is one of the more popular Z68 boards, so it is unlikely that there is a design problem.

    One thing you can try:
    Unplug the power cord from the PSU. Wait a few seconds, plug it back in, and try to reboot. Try this several times. If the system boots each time after unplugging the power cord, your PSU is the problem.

    You can also try breadboarding your system to eliminate possible shorting problems with your case.

    The following is an expansion of my troubleshooting tips in the breadboarding link in the "Cannot boot" thread.

    I have tested the following beep patterns on Gigabyte, eVGA, and ECS motherboards. Other BIOS' may be different, but they all use a single short beep for a successful POST.

    Breadboard - that will help isolate any kind of case problem you might have.

    Breadboard with just motherboard, CPU & HSF, case speaker, and PSU.

    Make sure you plug the CPU power cable in. The system will not boot without it.

    I always breadboard a new build. It takes only a few minutes, and you know you are putting good parts in the case once you are finished.

    You can turn on the PC by momentarily shorting the two pins that the case power switch goes to. You should hear a series of long, single beeps indicating memory problems. Silence indicates a problem with (in most likely order) the PSU, motherboard, or CPU. Remember, at this time, you do not have a graphics card installed so the load on your PSU will be reduced.

    If no beeps:
    Running fans and drives and motherboard LED's do not necessarily indicate a good PSU. In the absence of a single short beep, they also do not indicate that the system is booting.

    At this point, you can sort of check the PSU. Try to borrow a known good PSU of around 550 - 600 watts. That will power just about any system with a single GPU. If you cannot do that, use a DMM to measure the voltages. Measure between the colored wires and either chassis ground or the black wires. Yellow wires should be 12 volts. Red wires: +5 volts, orange wires: +3.3 volts, blue wire : -12 volts, violet wire (standby power supply): 5 volts always on. Tolerances are +/- 5% except for the -12 volts which is +/- 10%.

    The gray wire is really important. It should go from 0 to +5 volts when you turn the PSU on with the case switch. CPU needs this signal to boot.

    You can turn on the PSU by completely disconnecting the PSU and using a paperclip or jumper wire to short the green wire to one of the neighboring black wires.

    A way that might be easier is to use the main power plug. Working from the back of the plug where the wires come out, use a bare paperclip to short between the green wire and one of the neighboring black wires. That will do the same thing with an installed PSU. It is also an easy way to bypass a questionable case power switch.

    This checks the PSU under no load conditions, so it is not completely reliable. But if it can not pass this, it is dead. Then repeat the checks with the PSU plugged into the computer to put a load on the PSU.

    If the system beeps:
    If it looks like the PSU is good, install a memory stick. Boot. Beep pattern should change to one long and several short beeps indicating a missing graphics card.

    Silence, long single beeps, or series of short beeps indicate a problem with the memory. If you get short beeps verify that the memory is in the appropriate motherboard slots.

    Insert the video card and connect any necessary PCIe power connectors. Boot. At this point, the system should POST successfully (a single short beep). Notice that you do not need keyboard, mouse, monitor, or drives to successfully POST.
    At this point, if the system doesn't work, it's either the video card or an inadequate PSU. Or rarely - the motherboard's PCIe interface.

    Now start connecting the rest of the devices starting with the monitor, then keyboard and mouse, then the rest of the devices, testing after each step. It's possible that you can pass the POST with a defective video card. The POST routines can only check the video interface. It cannot check the internal parts of the video card.
  8. Thanks for your suggestions.
    I have received a new MB from asus, and everything seems to me ok so far.
    I think it was just a defective MB...
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