Issues with power on with new computer

[draxon]

Computer specs

pentium D 3.0ghz 775 socket
geforce 7600 gtx
2gig ddr2 ram corsair pc 5800 655mhz
MSI P4N diamond nvidia Nforce motherboard

So far building this new computer has been a pain in my rear ... Built about 12 of them now and this is the only one really stumping me... started out with it starting up but no video would display on the monitor... i tested the ram and graphics card in a friends computer ... so i thought maybe the motherboard had a faulty pci express slot.... so i replaced it... same thing.... so down to the last possibility left being the processor i just replaced that. Hook everything back up and now when i hit the power switch the power supply goes on, off, on, off. You can hear the fan kick in and the lights inside it blink on and off. I tried my old power supply and it did the same thing.... I dont see a processor causeing the problem. And it would power up just no video display before i switched the processors out.


Any suggestions on what might cause this. I've tried unplugging everything and plugging back in but get the same issue

 

[Rick]

A bad PCI card can cause a simliar issue. You said you disconnected everything, but try disconnecting the PCI cards too.

You may have already done this, but totally disassemble the computer, take the board out and set it up on a table or something... Plug in the PSU, memory, cpu + hsf and video... See if you get anything. We can at least make certain[/b] its one of these components.

Also make sure you unplug any wiring you may have to your front USB, firewire or audio ports. Miswiring or shorted out ports may cause a simliar problem.

 

[draxon]

Ok, I've removed everything from my case and was using just the graphics card CPU/fan and PSU. And i turned it on using a flat head screwdriver rather than my case to try and eliminate one more thing. Same thing occured... so i tried swaping my processors to the one i had previously. No more of the on off stuff. But still no video... tried my new processor again. and it fired up fine this time. It stays running no more on off stuff.... (confusing the hell out of me now). So I put one chip of memory in hooked my graphics card to my monitor. But it still shows me no video display.. just the monitor self test saying monitor is working properly please check cables.



also just thought of one other thing.... which id like to shoot myself if it was really this simple... But could it be lack of power why im not getting video display? I have a 500 watt power supply which i would hope is more than i need... but the parts i have seem to be rather power intensive. Graphics card requires 400watt power supply and uses two of my power cords from my psu. and the mother board requires 400 or 450watts and has a 24pin power cord ( which i bought a 20 to 24pin adapter for ) has the normal 4pin and also takes one of the normal power cords you would use to plug in everything else.