Can't power up new PC

rodash

Distinguished
Sep 21, 2004
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18,510
Hi,
I'm assembling a new PC and I'm having trouble getting it to fire up. Everything appears to be connected OK but it's just not happening. I can't work out if it's a power supply problem or a motherboard one.

When I press the power button on the front panel of the case, the power supply and fans all power up for a fraction of a second, then die. This happens with all three fans in the case (CPU fan, SYS fan, rear exhaust fan) as well as the fan in the power supply. The power duration is about 1/10th of a second, if that. It's as though something is quickly killing the power, for whatever reason. Strange thing is, when I press the power button again, nothing happens. But if I turn the power off at the power point, and then press the case power button again, the same short power-up occurs.

I've disconnected the two case fans, so I've only got the CPU fan connected, but still the same thing.

From what I have said, does this appear to be a power supply problem? I'm guessing the motherboard is killing the power cause some setting is wrong. Can anyone please help? Any help greatly appreciated.

The configuration of hardware I have assembled is as follows:

Antec Super Lanboy case
Antec 480w True Blue power supply
Gigabyte GA-81915P motherboard
Pentium 4, 530 LGA775 3Ghz
Kingston KVR400 dual channel 2 x 512mb memory modules
GeCube Radeon X300 PCI Express graphics card
Seagate SATA 200G hard drive
Gigabyte DVD writer
FDD


I have installed the memory modules into banks 1 and 3, which is the configuration for dual channel.

The front case fan is attached to the SYS FAN connector.
The CPU fan is attached to the CPU FAN connector.
The rear exhaust fan is plugged into one of the power supply leads.
There is nothing attached to the NB FAN connector.
I have attached the front panel power switch and rest buttons to the appropriate connectors, with the correct pin configuration.


I haven't set any jumper settings on the board because there doesn't appear to be any, and also because there's nothing in the installation booklet about setting jumpers. I'm presuming jumpers don't need to be manually set.
 
I have seen these kind of power issues on PCs at work. Generally what I have done to resolve them is switch the voltage at the back of the power supply from I believe 115v to 220, then back to 115. How many outlets have you tried?

On a Compaq that I had, that was doing the same thing, it was the front bezel that was the problem. It was not seated in correctly, so maybe something is up with your power switch. It is just a guess, but I would try to remove the front cover, and try to power it up that way.

Just some food for thought, good luck!

- Shinobi


Every great journey begins with the first step.
 
Normally that type of behavior is caused by the board protecting itself from a short circuit. And those short circuits are normally caused by one of the standoffs not lining up with a mounting hole, but instead shorting a circuit on the back of the motherboard.

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Crashman,
What you say makes sense. I'll take the board out and try it out of the case. I should have done that in the first instance ... in too much of a hurry to get it working.
Thanks for the reply ... greatly appreciated.
 
i have the same problem .i build a pc with antec aria 300watt universalinput power supply amd athlonxp2600 barton and chaintech 7vf4 motherboard.its pwer for few sec and after nothing.exatly the same problem with rodash...rodash did you fix it;
 
I THINK my problem e was the fan.it was for 3200 cpu and my cpu is only 2600
That doesn't make a difference. If you don't have anything shorting the motherboard, and I take it when you jump the PSU it stays on? If so, then start pulling unnecessary stuff out of the computer. Start with the PCIs, a bad PCI can do this also on some boards. Pull PCIs out one at a time, you can see what is causing the problem, if none of those work, try the AGP, you might not have any graphics, but see if it stays on. Then unplug all your drives, then move down to one RAM chip (If you have two). Somewhere in there it will probably stay on, then you will have an ideal of which component was causing the problem.


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