The oddest power-up problem

[NewbieA]

Okay--I've been looking through the boards and haven't found any problem like mine:

Brand new computer, self-built, GA-8IHXP mobo, P4 2.26GHz, 512 MB ECC 1066MHz RDRAM. All the cables connected, the power supply is switched on in the back and the soft power button is depressed.

The fans (all of them: PSU, CPU, mobo-northbridge, case intake, case exhaust) all turn on and then immediately shut off--total runtime from start to finish is roughly half a second. It's almost as if something is triggering an automatic shut-down mechanism RIGHT after the power goes on.

What I've done:

I don't think the problem is with the power supply because my PS/2 devices do seem to be getting power. I have a wireless mouse and the little green light on the RF receiver is on whenever the PSU is on, whether the computer is in its funny on/off routine or not. Likewise, the keyboard LED's blink when the PSU is turned on, indicating it receives power.
I don't think the problem is with the power switch because I unplugged it and tested the darned thing with a multimeter: when the switch is pressed, it completes its circuit and then breaks it again, just as it should. Also, I have tried the reset button to no avail (But its switch works fine as well)

Please give me any advice you can, even if you have any idea WHERE the problem is it could be helpful. I was careful to plug all the cables and cords in the right war (I think), and all the components are brand new. Thank you in advance.

[mjc]

Strip it down to the RAM and the video card, then see if it will POST...if so add in one device at a time and see if it will continue to POST. (Power down completely and unplug or plug into a power strip and kill the switch on the power strip before making any changes.)

Also make sure that any jumper settings are correct for the CPU you are using.

You may want to remove the motherboard from the case and try it on a piece of cardboard to reduce the possiblity of a short circuit to the case.

[NewbieA]

So...

I took out all the expansion cards and IDE cables except for my AGP video card and started it up. Fans... whirr... stop. Same problem.

Then, I took out the motherboard and placed it on cardboard. Fans... whirr... stop. Same problem.

My problem is this: Which manufacturer do I call? Is it the motherboard (my current suspect, since the juice doesn't even seem to flow), RAM, CPU, or video card? I don't really have any "spare parts" to test with, so is there anything I can do to guess?

If not, would it do any good to take it to my local custom computer/repair shop (even though I purchased no parts there) and see if they can find something I can't? What might I have done that could cause this problem? Thanks in advance.

[ranchdog]

Couple of questions....

Is this Gigabyte Mboard compatable with ECC type memory?

Is the CPU heatsink fan plugged into the proper fan plug?
BIOS may not be detecting any HS/F rpm and shutting down
the system.

Is the CMOS jumper in the proper position?

Guess that's three.


RD.

[NewbieA]

Yup, both motherboard and memory are ECC.

Yup, the CPU heatsink/fan is plugged into the place labeled CPU_FAN on both the instruction manual and the board itself

And, the CMOS reset jumper is set to "normal." There aren't any other jumpers because the clock and ram speeds are configured via BIOS.

Thanks for all your help, even though the problem still seems to elude us. On a side note, I took out even the video card (leaving JUST the CPU and RAM), and unplugged the PS/2 devices. The problem is unchanged: fans (and likely entire computer) get one "shot" of electricity. Result: the fans spin on and coast quickly to a stop. I'm getting awfully close to sending the motherboard back. Does anyone out there think (as I am coming to) that it is a motherboard problem (specifically, a defective device)? Or could there still be something with the CPU or RAM?

[Sylvander]

Hello NewbieA

QUOTE
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System Boot Sequence
The system BIOS is what starts the computer running when you turn it on. The following are the steps that a typical boot sequence involves. Of course this will vary by the manufacturer of your hardware, BIOS, etc., and especially by what peripherals you have in the PC. Here is what generally happens when you turn on your system power:
1. The internal power supply turns on and initializes. The power supply takes some time until it can generate reliable power for the rest of the computer, and having it turn on prematurely could potentially lead to damage. Therefore, the chipset will generate a reset signal to the processor (the same as if you held the reset button down for a while on your case) until it receives the "Power Good" signal from the power supply.
------------------------------------------------------------------------
END OF QOUTE

It looks like your system doesn't even get to the start of the POST sequence. If it did and was failing to complete it. You should remove all but the keyboard and monitor and if it still fails to POST you have a fault with the motherboard or something on it. You don't even begin POST. This suggests a PSU problem but perhaps it detects a motherboard problem and protects itself.
My diagnostic charts recommend disconnecting all devices from the PSU and testing the voltages. If the power input is ok but the output voltages are wrong the PSU is faulty.