Motherboard dead?

I used my Jeantech 1000W PSU with an ASROCK N68C-S UCC socket AM3 motherboard and I think I have damaged the motherboard (possibly other components too) because of a silly mistake

The PSU is modular but I could not find a 4 pin power connection to the motherboard (the ASROCK N68C does not have an 8 pin slot) I assumed I would be able to "fit" the 8 pin adapter into the 4 pin slot (and managed to do so without any problems) When powered up there was no motherboard/Fan activity at all and after a few seconds it started to make a high pitched sound. Ten seconds later I smelled burning coming from the PSU and quickly turned it off.

I did the "paperclip" test on the PSU and it appears to be dead (also out of warranty, -£100). To clarify I used another 600W PSU and it passed the paper clip test (fans spinning as usual)

I tried this 600W PSU with the motherboard, and it created the high pitched sound/no activity.

It appears the motherboard is also dead but I fear the other components may be damaged. The Processor and RAM (Phenom II x4 955/4gb DDR3 1600) are only a week old. Also I had the nvidia 275GTX in there :(


Could anybody clarify that this was caused by putting the 8 pin into the 4 pin socket? I assume now that they are different voltages...

Is it likely other components are damaged too? From what I understand the 4/8pin motherboard socket is FOR the CPU, so I'm worried the CPU could be completely fried

Where should I check for signs of physical damage? I cannot report any and have inspected the motherboard quite thoroughly. The RAM/GPU connections do not have any "melting/discoloration" so I hope that is a good sign. I have not checked the processor yet.

Could there be a chance the motherboard has survived and it is in fact the processor which is broken?

Thank you for any support. For your information the Processor/RAM/Motherboard is all under warranty (the PSU/GPU is not)
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  1. UPDATE;

    after removing the processor/resitting it and putting in 2x 1gb DDR2 RAM modules, it is magically showing some life again...

    Previously there was a high pitched sound/no activity at all

    Now the CPU fan spins as usual, the GPU fan is spinning, and it does not turn off until I turn it off

    But - whatever I try, there is NO display on the screen - I have tried a 9800GT GPU, and the onboard graphics.

    I'm trying to get a signal with just the following connected:

    PSU --> 4pin/20pin @Motherboard
    Case --> Mainboard switch connected
    GPU --> 6pin power adapter connected
    monitor --> nvidia 9800GT GPU

    Seems to be working, but no display...

    any ideas? the GPU slot is faulty?? does it need a hard drive or something else connected to show video? This is confusing now :/
  2. any suggestions? I have authorised a return for later today and I'm stuck in limbo whether it is the motherboard or not :/
  3. Work systematically through our standard checklist and troubleshooting thread:
    I mean work through, not just read over it. We spent a lot of time on this. It should find most of the problems.

    If not, continue.
    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: 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.
  4. thank you jsc I am running through these solutions right now and will report back when I'm done. In advance I would like to mention again that I suspect a hardware failure (possibly the motherboard's PCI express slot)
  5. I just checked specs for your PSU. It is supped to come with a 4 pin modular cable for CPU power. Now, when you plugged the 8 pin cable into the CPU power plug, did you use the 8 pin plu on the cable permanently connected to the PSU or did you use one of the modular cables?

    If you used one of the modular cables, you used an 8 pin PCI-e cable. They are wired differently. Using one of those will result in a 12 volt short to ground. If you did, your PSU should have nondestructively shut down.
  6. Thanks for looking into this.

    I originally used the 8 pin permanently connected cable of the Jeantech 1000W. I had four of the parts connected to the motherboards 4 pin plug the other 4 pins were not connected to anything, yet it seemed like a firm/correct connection.

    I didn't use a modular cable for it. After the incident/malfunction I found a modular 4 pin cable (the one I should have used originally) but now it is too late since the PSU has been fried

    The 600W PSU I'm now using is not modular, but it has a 4 pin/20pin for my motherboard and I can confirm that it works

    I am currently attempting a CMOS reset and will report back shortly
  7. I reset the CMOS, and even tried another battery (identical)

    Nothing to report other than the CPU fan/PSU fan/GPU fan all operating normal, but NO DISPLAY

    Also tried a lot of RAM configurations/DDR2/DDR3 and haven't had any luck. Just to note, I can't get the system speaker to work, which may have been useful for diagnosing certain things. I will also mention that the CPU/GPU/PSU fans are all showing normal activity even when no RAM is installed (I don't know if this is normal)

    I'm racing against time because I authorised a motherboard return and I'll have someone around to pick it up in a few hours! Although it now appears that a return is what I'll end up doing anyway
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