Startup - powerdown, powerup

Hello,I decided to upgrade from my x38-DQ6 mobo. I bought a Gigbyte GA-P67A-UD3-B3, an i5-2500 & a CMX8GX3M2A1333C9 (2 X 4GB) xms3.
When I connect power to the PC all the fans are running but after 5 seconds the pc powers down for 3 seconds the up for 5 then down for 3secs. This cycle repeats until The power to the PC is turned off. I've clr cmos, same fault. Removed Cmos for 4 hrs, same fault. Changed cmos bat with a known good one, same fault.
Disconnected all back panel, all drives, all sata data cables, same fault. Taken mobo to inspect underneath & case, refitted i5, same fault. tried a new ram KVR1333D3N9K2 (2 x 2Gb), same fault. Sent ram back to supplier but Corsair confirm the XMS3 as fully compatible with the UD3-B3.
has anyone seen this before. Any suggestions where I go next?
Help, please.
15 answers Last reply Best Answer
More about startup powerdown powerup
  1. No short(s) (e.g. from an unnecessary standoff)? Heatsink seated correctly?
  2. Best answer
    Here is what is happening:
    You turn on the computer. In about 1/2 second, the PSU outputs stabilize. After they stabilize, a control signal called something like "PowerGood" goes to a Logic HIGH (5 volts). This removes a hardware reset from the CPU and the system boots. shortly after, one of the outputs drops out of tolerance. This brings the "PowerGood" signal to 0 volts and forces a hardware reset/reboot cycle. At this moment, the PSU load decreases. The output voltage stabilizes. And the complete cycle starts again.

    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.

    You have replaced the motherboard. Do you have all the case standoffs in the right place?
  3. Hi JSC
    Thanks for you info. I went thru it all with great intent. I like your Breadboard idea. Since I have gone back to my original config
    & it works flawlessly, I have to rule my PSU in good shape. Or is that wishful thinking? With the 2 sets of RAM used on the new mobo & both failing, does that indicate the RAM is probably OK. I will double check the standoffs again. I am my Antec Atlas cas has no threaded hole to mount a standoff for the UD3-B3 front centre mounting hole. Not causing a problem but I do exercise care when applying pressure to fit RAM. The corsair video linked in your reply is a good one. At 1st glance it is very close to my problem but with my X38 running well I think I have to keep looking further. Re beeps, I don't get any nor can get to bios.
    Thanks again. I appreciate your input.
  4. On the Gigabyte boards pressing the [Delete] key right after the system does one short beep should get you into the BIOS.

    Keep in mind ...
    It seems like fewer and fewer cases include the system speaker. If one is not included on the motherboard, you should buy one.
  5. Hi Jsc
    I don't get any beeps at all & no output to monitor when it's connected. This fault is the same whether I have nothing connected except HSF & RAM or all back panel, all drives & everthing else. Yes I had to buy a little speaker to fit to the X38-DQ6. works well.
  6. If you breadboard with just PSU, motherboard, CPU & HSF, and case speaker and you get silence; either the PSU, motherboard, or CPU (in that order) is bad.
  7. jsc said:
    If you breadboard with just PSU, motherboard, CPU & HSF, and case speaker and you get silence; either the PSU, motherboard, or CPU (in that order) is bad.

    Thanks jsc. I'll update when I get sorted with supplier.
    Have a great day
  8. Hi everyone
    Suppliers have tested the XMS3 as ok.
    It has been sugested to me that a Bios update may fix my problem. Has anyone any comments on that. Before I sent the ram to be tested, I had my PC to a local computer pro. He got to bios by changing the ram to one of his test modules. He also commented about the possibility of a bios issue. After he got to bios we decided the problem was faulty or incompatible ram. Seems maybe not so.
    At the moment I seem to have a few options:
    1. send mobo complete with the i5 to the supplier to test with the XMS3.
    2. Back to the local bloke to try for a bios update.
    3. Buy another XMS3 (CMX8GX3M4A1333C9) 4 X 2Gb that is on the QVL.
    Any comments welcombed
    Have a great day
  9. Check the PSU, preferably by replacing it with a known good one.
  10. Hi PreferLinux
    Thanks for the comment. My PSU is an Antec TruePower 550W. It runs my system well. I believe the UD3-B3 at 95W is less than the X38-DQ6 so I'm reluctant to doubt it at the moment. Will not rule it out, but until I can rule out the M/B & bios I'll stay focused on them.
    Thanks again
    Have a great day
  11. Try to upgrade the BIOS then. If that doesn't work, try a different board. If you have another board the same available (say at the computer technician), i may be easiest to check with the new board first (with old BIOS, preferably).
  12. PreferLinux said:
    Try to upgrade the BIOS then. If that doesn't work, try a different board. If you have another board the same available (say at the computer technician), i may be easiest to check with the new board first (with old BIOS, preferably).

    Hi preferLinux. The board is going back to supplier for testing today. I'll update when I can. Thanks again. Have a great day.
  13. Hi everone
    This morning I had a call from my supplier. Their tech team have identified my problem as a faulty CPU. No details yet but the i5-2500 is on its way to be replaced. Tech team say these Intel units are usually rock solid. Not so this one. They are also happy to report the Corsair CMX8GX3M2A1333C9 (2 X 4Gb) kit has been tested in my GA-P67A-UD3-B3 and found to be compatible. So I've had a win - win today.
    Thanks to everyone that replied. When I get the details on the CPU I'll give you an update. Link attached is to an article that came in Toms Hardware Newsletter recently. Worth a read.
    Have a great Easter,2907.html
  14. Good to hear!
  15. Best answer selected by Roscob.
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