Sign in with
Sign up | Sign in
Your question

New build shutting down before POST

Last response: in Motherboards
Share
April 13, 2011 11:50:31 PM

Hello all, I would really like your help. Note sure where to post this. hopefully here is right. I recently built a new computer to replace the one im currently on. This wasnt my first build, so it was only about a hour before everything was in the case and ready to be booted up. The first boot up it powered down before the POST beep. All the fans were working. So I sat back to think to myself and then it tries to power back up, without me touching the power button on the case. I then did something stupid, I switched the voltage on the PSU from 115 to 230 and started the computer. This time however it didn't power down, it stayed on for 5 minutes or so while i was crossing my fingers hoping to hear the post beep. I heard nothing, however all the fans were working and there didn't seem to be anything obvious wrong with it. I started unplugging unnecessary things to see if I could find the culprit, note this is while the PSU is still set to 230v. I tested the hard drives, Ram in all slots and different video cards to no avail. I got on my laptop to do some research and it looks like it could either be the PSU, CPU, Mobo, or a combination.

System Specs

  • PSU- Raidmax Hybrid 2 RX-630SS 630 watt
  • CPU- Core i5 2500k
  • Mobo- MSI P67a-C43
  • Ram- 4gb G.Skill DDR3 1333 PC3 10666
  • GPU- Nvidia GTX 260
  • HDs- 2x WD RE4 250gb


    After a break (all that troubleshooting is really tiresome) I decided to try it with a new PSU. I ripped the psu out of my old computer (the one im on right now) and plugged everything in. Double checked that the voltage was set to 115 and powered it on. Same thing happen, shuts off after no longer than a second. No POST.

    Trouble shooting methods I have tried:

  • Different PSU
  • Different video cards
  • Different hard drives

    Methods I haven't tried yet.

  • Have yet to rip the motherboard out and see if it will POST outside of the case
  • ect

    Thursday I will take out the Mobo and double check the CPU and every thing else and see if it will POST before I send it away to be RMA'd.

    Thankyou for your help, I really appreciate it. I'm over here about to pull my hair out. :fou: 
  • More about : build shutting post

    April 14, 2011 12:10:33 AM

    I forgot to add, after I smarted up and put the PSU back to 115v and started the computer, i paid attention to the CPU power phase lights. When powering on the computer, the led closest to the back panel would stay on, after about half a second I would see the other three leds turn on for just long enough for me to see the lights flicker. Thats right when the computer shuts down. Also I dont think I mentioned must detail about this, but while set to 115v the computer would keep on trying to start, even after shutting down. It would go something like this:

    00:00 Power button pressed, computer turns on.
    00:01 The three leds flicker
    00:01 Computer shuts down

    00:06 Computer turns back on, without pressing the power button.
    00:07 The three leds flicker
    00:07 Computer shuts down

    This cycle continues until I pull out the plug from the power supply.

    I decided to add a few pics of the Power phase lights.

    Right after computer turns on.


    Right before system shuts off





    m
    0
    l
    April 14, 2011 12:40:19 AM

    Forgot to add that im not using a optical drive, if that matters.
    m
    0
    l
    a c 156 V Motherboard
    April 14, 2011 1:21:11 PM

    I have several Gigabyte motherboards. I ignore the phase lights because they don't seem to tell me anything useful.

    Work systematically through our standard checklist and troubleshooting thread:
    http://www.tomshardware.com/forum/261145-31-read-postin...
    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.
    http://www.tomshardware.com/forum/262730-31-breadboardi...

    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.
    http://www.youtube.com/watch?v=5FWXgQSokF4&feature=yout...

    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.
    m
    0
    l
    !