[Fault] System boots for less than 1 second. Then wont boot again.

A quick bio to start off:
I'm a RADAR Tech for the USMC in Okinawa, Japan and have a good understanding of how a computer works.

About my problem.
I bought all my parts online and they arrived monday/tuesday. I set everything up, being careful and meticulous as i always try to be. Cautious of shorts, properly grounded and ESD free.

Turned the system up and installed Windows 7. The system ran fine for about a day. I went to play a game with a friend of mine and a little ways in, about an hour or less, the system cut off.

Now it will only start for less than a second. The MoBo LED's are lit when power is applied. When either power button is pressed(one on the case, one on the MoBo) all the fans spin for less than a second and the case LED's light for less then a second. It wont do anything else unless power is completely removed until the LED's on the MoBo extinguish, and is then power is reapplied.

There are no system speakers so i cannot check the beep codes, but i assume that since the system wont stay lit for more than a second there wouldn't be any beeps.

Here are my specs along with the troubleshooting steps I've taken thus far:
CPU i7 920
Motherboard ASUS P6T
RAM G.SKILL Trident 4GB (2 x 2GB) DDR3 2000 1.65v
CPU HSF Stock
Video Card EVGA GeForce GTX 275
Power Supply hec Zephyr MX-750 750W
Hard Drive Western Digital Caviar Black 750gig
Operating System Windows 7
Case Coolmaster ATX Mid Tower
At the time I also had a 500gig external HDD and a camera that was powered off plugged into USB ports. Of course my mouse and keyboard were plugged in, both USB, and my 21.5" LCD.

Troubleshooting steps taken:
Already checked READ before posting about boot problems!
Tried completely reassembling the system and breadboarding it, all to no avail.
I tried resetting the CMOS per the MoBo manual and pulling the battery.
Lastly i tried some steps listed here. With every PSU cable removed i shorted the PS_ON signal to ground and the PSU spun for a second then failed. So i think it's safe to assume that is the problem. I will try and find a reliable PSU and test it with the rest of the system this weekend.

I'd like advice on whether i should RMA this for a new one from the same manufacturer or try one with a higher wattage. I was pretty sure that 750, while not high by today's standards, would have sufficed.

Any advice or help is appreciated. I'm mostly posting this as a reference to anyone with a similar problem.

[Edit PS_OK fixed to PS_ON]
4 answers Last reply
More about fault system boots second wont boot again
  1. Commoner said:

    Troubleshooting steps taken:
    Already checked READ before posting about boot problems!

    With every PSU cable removed i shorted the PS_OK signal to ground and the PSU spun for a second then failed. So i think it's safe to assume that is the problem. I will try and find a reliable PSU and test it with the rest of the system this weekend.

    Do you mean the PS_OK signal (gray wire) or the PS_ON command (green wire)? It should be the green wire.

    If the bare PSU will not start up when you momentarily short the green wire to ground, the PSU is bad. A warning here: Some PSU's say they need a minimum load of 1 amp on the 5 and 12 volt outputs. I have never that happen, but just in case, my troubleshooting kit includes a male molex connector with 5 watt 4.7 ohm resistors wired between the 5 volt (red) and 12 volt (yellow) lines and ground to load the PSU. (Yes, the resistor across the 12 volts and ground is underrated. Should be about 25 watts, but it wouldn't be plugged in long.)

    The PS_OK line is a control line that is supposed to go to a logic HIGH after all the PSU outputs have stabilized. When that happens, it removes a hardware reset from the CPU, enabling the boot process. No PS_OK, no boot.

    A 750 watt PSU is more than adequate for your build. And brands? Although I have a couple of semi-old Antecs (550 and 650 watt TP3's) around, I have gone to Corsair for power (750TX, 550VX, and 400CX).

    Two more comments:
    You really need a system speaker.
    I always breadboard a new build. It gives me a fair amount of confidence that I am installing known good parts in the case.
  2. That was a typo and for some reason i can't edit my post.

    I meant PS_ON.

    I think one of the guys i work with might have a test kit.

    I'll check around for some system speakers, i remember seeing a link to some on one of these posts.
  3. I'd put an Antec TP-650 or Corsair TX-650 in there if you are gonna stick with 1 GFX card....850 if ya think ya might go to 2 GFX cards someday.

    If you wanna OC in the 4GHz range, then I'd change those recommendations to the Antec SG series or Corsair HX series.
  4. Commoner said:
    That was a typo and for some reason i can't edit my post.

    In the lower right, you have 3 icons. The middle one with the lightning bolt on a gray background is the "QuickEdit" button.
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