New computer won't power up...

[beansbaxter]

Just to preface this, I build computers all the time, which is why I am stumped and asking for some help here...

Putting together a new machine, quick rundown on the specs that matter here:

Asus K8V-X Motherboard
AMD Sempron 3000 CPU (Retail)
Corsair 512MB DDR400 Memory
Asus AGP8X 64Mb GeForce4000 Video Card

Ordered everything off of Newegg, put everything into a machine with a new Antec 400-watt power supply, plug it all up...

When the power supply is switched to on, the green light on the Asus mobo lights up green of course, but when I turn the power switch on, nothing happens. I can see a quick jolt of current go into the CPU fan, as it looks like it feels that little "kick" of electric juice, but nothing happens. I can turn the power supply off, then back on, and the same thing happens.

I've checked my connectors and jumpers, everything seems fine. I've done this a thousand times, but this one wont kick on for some reason.

Any ideas??????????????????

 

[FlyingPenguin]

Most modern mobos require an ATX12v cable (4 pin molex) to be connected from the power supply. If it's not connected, the computer won't start.

Hope this helps...

 

[beansbaxter]

Yeah the standard ATX connector and the additional 4-pin power connector is also plugged in. On the mobo, the green light is turned on, just nothing powers up.

I think it is odd the CPU fan which is directly connected to the motherboard does not even kick on at all.

 

[deathwalker]

May i suggest that you do a bios reset and see if that does it. I have seen this prolem before and it was once solved via a bios reset.

 

[beansbaxter]

Yeah, I tried to reset the BIOS using the jumpers onboard, and that didnt work. I plugged the CPU fan into a working motherboard and the fan kicked on when I turned that computer on. But when I put it back on this setup, the fan doesnt turn on and again, the green light on the mobo is on.

Is this is a faulty motherboard? Is there any other symptom or cause I should look into to rule other stuff out?

 

[amdskip]

I would remove the motherboard from the case because there might be something slightly misaligned causing a short. Other than that and swapping out hardware, you sound like you have a bad motherboard.

 

[mechBgon]

Another possiblity is that the mobo needs a BIOS update to support this particular Sempron. Asus CPU-support looker-upper lists three flavors of Sempron 3000+ with the required BIOSes. Asus is in the habit of sticking a sticker on top of the BIOS chip that has the BIOS revision 1007 or whatever, so that could be an easy way to tell what BIOS it shipped with. They don't specifically say that it won't POST or run with a lesser BIOS, and usually the symptoms of a BIOS Catch-22 are that it does run but not POST, so I could be off base on that idea

If the out-of-case test works, then maybe there's a stray standoff in the case in this position where the mobo doesn't have a hole? or maybe the EMI springs on the I/O shield fell into the USB ports?

Good luck!

 

[thepd7]

Originally posted by: mechBgon
Another possiblity is that the mobo needs a BIOS update to support this particular Sempron. Asus CPU-support looker-upper lists three flavors of Sempron 3000+ with the required BIOSes. Asus is in the habit of sticking a sticker on top of the BIOS chip that has the BIOS revision 1007 or whatever, so that could be an easy way to tell what BIOS it shipped with. They don't specifically say that it won't POST or run with a lesser BIOS, and usually the symptoms of a BIOS Catch-22 are that it does run but not POST, so I could be off base on that idea

If the out-of-case test works, then maybe there's a stray standoff in the case in this position where the mobo doesn't have a hole? or maybe the EMI springs on the I/O shield fell into the USB ports?

Good luck!

I am having the problem you just said. Everything comes on but it won't post. I assumed this was a mobo issue as I have heard that my board (dfi) is squirrely. Can you flash BIOS without posting? I tried resetting BIOS, it didn't work.

edit: I realized I didnt give enough info.
I am running Antec Sonata 380W, DFI lanparty ultra-240 nforce3, AMD 64 3400+, x800xt AIW, SATA HDD. I tried unplugging everything, different ram, different video card, taking out battery and clearing cmos. Basically I turn it on and all the fans rev up, drives whir, cd roms will open, but the screen changes back and forth every 3 seconds or so from black to slightly black. Sooo I am pretty sure I need to flash bios but I have no idea how to do that when nothing will post. Thanks in advance,
David

 

[beansbaxter]

If the motherboard and processor is all that is installed into the case, the power is all connected up, and you turn on the system - shouldnt the CPU fan (which is connected to the mobo) still kick on no matter what?

 

[beansbaxter]

Originally posted by: mechBgon
Another possiblity is that the mobo needs a BIOS update to support this particular Sempron. Asus CPU-support looker-upper lists three flavors of Sempron 3000+ with the required BIOSes. Asus is in the habit of sticking a sticker on top of the BIOS chip that has the BIOS revision 1007 or whatever, so that could be an easy way to tell what BIOS it shipped with. They don't specifically say that it won't POST or run with a lesser BIOS, and usually the symptoms of a BIOS Catch-22 are that it does run but not POST, so I could be off base on that idea

You raise a good point...so I ask how do I flash the BIOS on a motherboard that wont post up. This is a Socket 754 mobo and I dont have any additional processors of that size. My experience in the past with Asus, Abit, and Epox, have been they still read the processors but they are read incorrectly, usually underclocked. Once the BIOS has been flashed/updated and the correct settings have been entered in the BIOS (FSB freqency) then it reads correctly. But they always booted. Have things changed?

 

[wpshooter]

Have you tried a different power supply ?