power supply or motherboard?

piazon79 · July 26th, 2009, 10:52 AM

I recently have a pc that won't start. The power kicks on but there is no post and no video at all, i can't even get in to the bios. I have an OCZGXS700 power supply that powers dual SLI video cards, it is 700 watts. I have a power supply tester and it tests bad. The only green led that doesn't light up is the -5v led, and of course the red led lights up that indicates not to use the power supply. Does this sound like a power supply issue even though the power supply still kicks on? Again, there is no post and no video at all, this power supply also has the blue led that lights up the inside of the power supply box which still turns on as well. Any thoughts?

Thanks!

Steve R Jones · July 26th, 2009, 10:55 AM

If the pc was working fine one day and quit the next ->Power Supply

piazon79 · July 26th, 2009, 11:11 AM

eventhough the powersupply still kicks on? Im hoping this is the case since ide rather replace the powersupply than the mobo

Jim Murphy · July 26th, 2009, 12:08 PM

If the 5V side of the supply is not working the computer certainly will not operate. Different sections if the computer use different voltages to preform their functions. If one section is out then certainly nothing will operate properly. Get a new power supply. You won't know if the motherboard was take out also until you install a new PS. Try to get the PS at a store that will let you return it if the motherboard is also bad or actually caused the PS to fry. Jim

Quote:

Originally Posted by piazon79

I recently have a pc that won't start. The power kicks on but there is no post and no video at all, i can't even get in to the bios. I have an OCZGXS700 power supply that powers dual SLI video cards, it is 700 watts. I have a power supply tester and it tests bad. The only green led that doesn't light up is the -5v led, and of course the red led lights up that indicates not to use the power supply. Does this sound like a power supply issue even though the power supply still kicks on? Again, there is no post and no video at all, this power supply also has the blue led that lights up the inside of the power supply box which still turns on as well. Any thoughts?

Thanks!

piazon79 · July 26th, 2009, 12:28 PM

Thanks Jim. That was actually going to be my next question....if the PS could have blown out my MB as well. I wish there was a way to test a MB before i go and spend over $100 for a power supply that i won't need if the MB is bad too.

stroyal · July 26th, 2009, 01:06 PM

Can you borrow a power supply? Computer shops and most of us geeks have spare parts we have collected over the years, that we use to test computers. It is just about the only way, without factory test equipment, that even shops don't have.
A local shop could probably test the PS and motherboard, by trying a different power supply on your computer.

Memory can be tested with a program if the computer is running, and I don't see any reason a power supply tester shouldn't be reliable.

The rest of the parts would need factory test systems or by trying your parts in a known working computer, or by trying known working parts in your computer.

carl33p · July 26th, 2009, 02:35 PM

I have built over 300 PC's.
90% of the time, with your symptoms, its the motherboard that is defective. But take into consideration, that I'm referring to all new parts. And minus the power supply tester.

The best way to troubleshoot is swapping out parts with only the PSU, motherboard, CPU, and GPU connected.(outside the case) No other parts are needed for a computer to post.

Good luck in troubleshooting.

kurazy · July 27th, 2009, 04:37 PM

use another atx power supply if you have one . to test, your mb only needs 400 watts

piazon79 · July 27th, 2009, 07:18 PM

thanks everyone for your repsonses. As it turns out, it was a stick of bad memory. I have 4 1 gig sticks of ballistix RAM and one of them was bad. I tried each one individual and in all the slots and with the bad stick in didn't post or anything. plugged the other 3 back in and booted fine.