PSU issue?

Hey everyone.

I just finished my first build. Everything was looking great.
Started her up, went into bios, I could see the Ram the processor was fine, running at about 55'c using stock cooling.(Planing on upgrading later).

Thought i was successful in my first build.
Shut it down, Went away came back later to start installing my OS.
Won't start.
Unplugged/plugged the power back in, it starts for about a 1/4 of a second. then nothing.
Removed the hard drive/dvd still nothing.
Is this due to a faulty PSU? not enough watt/amp?

Or have i messed something up?


Intel i7 860
Asus 1156 Sabertooth 55i
Zotac GT240 AMP Edition
Corsair 4GB 1600MHz CL9 DDR3 Memory Kit(2 x 2gb)

Corsair 450W VX Series PSU - ATX12V v2.2

Plus a DVDRW & 3.5 SATA Harddrive.
10 answers Last reply
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  1. No chance it was "not enough watt/amp" problem. It could have been a PSU failure.

    You can do a paper clip 'jump start test' and see if the PSU is running. How to jump start test the PSU/.
    That should confirm that PSU is dead or alive.
  2. You don't need to take the PSU out of the case - just make sure you're disconnected from everything - except maybe a case fan.
  3. Thanks for helping.
    Just tried the jump start, The PSU Started and my case fan, so the PSU works.

    I checked all the internal connections there all good, also tried a different power cable, it did the same as before started for like a 1/4 of a second and then nothing.

    Any ideas?
  4. Run through the "System won't boot" checklist and see if you can find anything to help there.
  5. BlackSpiderWolf said:
    Thanks for helping.
    Just tried the jump start, The PSU Started and my case fan, so the PSU works.


    You do not know that. All you really know is that your PSU is producing enough 12 volt power to run a fan. You don't know if the 3.3 and 5 volt outputs are good. You do not know if the standby power supply inside is working. And you do not know if the "PowerOK" control signal is present.

    The only thing you do know is that the PSU is possibly not dead.

    Try to borrow a known good PSU. If you cannot do that, borrow 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.

    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.
  6. I've been though the whole "System won't boot check list" No good.
    Couldn't find a clear cmos jumper. only one I have is a clear RTC(real time clock) would this do the same? cleared it all anyway.

    Just tried bread boarding.(should of done this is start with)

    Motherboard on a wooden table. Nothing but the CPU/heatsink, the PSU on the table.
    Plugged the 24/4pins in, the same as before happens.
    First time I try to start it, the fans go for a 1/4 second then nothing.

    Tried the jump start with the motherboard connected. no good.

    I have a good PSU,
    (ATX 300, +12v 19a, +5v 30a, +3.3v 28a, -12v 0.8a,+5vsb 2a)
    Should be able to easily run just the motherboard and CPU right?
    Still no good started for a 1/4second then nothing.

    Would this happen to be the motherboard?

    The first time I plugged her in everything was great, shut down and never started again, but i didn't touch/change anything. Any idea what's happened?
  7. Sorry DP I'm not allowed to edit..

    Just got hold of a DMM, everything is what it should be.(PSU jump started no mobo)

    When connected to the mobo even jump started everythings dead.
  8. That 'fans go for a 1/4 second then nothing' is a clear sign it's failing the POST (power on self test).
    Since the HDD and DVD aren't part of the POST you can disconnect them during the breadboarding testing.
    Can you borrow a known good video card? And maybe a stick of RAM?
    You're looking at CPU, Motherboard, RAM or Video card as being the problem.
  9. I've been testing it with just the basics, Mobo, CPU/Heatsink and of course PSU.

    The CPU i removed, cleaned down, which was pretty terrible, the stock compound oozed a bit out the side(didn't touch anything) and had loads of air bubbles in it.(never using stock again..) Checked all the pins none broken/bent that i can see.
    put back on with Arctic 5 , using instructions from there site.
    No good.

    But i just tested with the new RAM(all positions/amounts).
    I Don't have any old that i know works and is compatible.
    The new GPU, and the one from this comp.

    Did all that since I'm unsure if it'll fail to boot when it detects missing ram/gpu and no system speaker.
  10. Update:
    After trying everything i could think of I've just noticed that the CPU LED lights up.(so fast I've just noticed it)

    Meaning there's an issue with the CPU, as I said above I've reseated the CPU, appiled new thermal compound etc. Is this a bust cpu?

    I'm going to try and get it replaced but might take 1-2 months since there out of stock.(and a new motherboard just to be sure)

    Before I go searching for a new CPU from somewhere else is there anything more i can try?

    More importantly any ideas what went wrong?
    Defective CPU/mobo?
    If so why did it start first time i tried it?

    The only thing i can think of is the 8pin power for the cpu, When the mother came it had a cover over 4 of the 8pins. So i used a single 4pin.
    Assuming that's what it wanted.(that's what it did start with)
    After searching the net I've found that most people can't get it to boot with just the 4 pins, and have to remove the cover and use an 8pin, then everythings fine for them..tried it..
    Could this of somehow blown it, never heard of lack of power blowing something..

    Just trying to find some answers so i can avoid it in the future.
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