Why won't my machine post?

July 19, 2006 3:58 PM

I just put together a pc from new parts. It won't post-- fans turn on, but that's it. No video signal, no power light, no beeps, cd trays won't open. Power supply is 400w and tested in another machine. What should my next steps be?

Feel free to ask me anything that I should have already told you.

posted by Mayor Curley to computers & internet (14 comments total)

Motherboard's toast.

Check to make sure you don't have any screw thingies in the wrong place on the backside, take the mobo back to the store, and get a new one.
posted by SpecialK at 4:01 PM on July 19, 2006

What the parts are?
posted by cellphone at 4:01 PM on July 19, 2006

You could also have a borked CPU, and an ok motherboard. Among other things. Trial and error, swap known-good with questionables.
posted by cellphone at 4:02 PM on July 19, 2006

cd trays won't open

This strikes me as odd...are you hitting a button on the CD drive itself? All the ones I've come across will open as long as they are getting power, regardless of what is happening on the data bus.

But if the fans are coming on, the drives should be getting power. Is the hard drive spinning up?
posted by trevyn at 4:14 PM on July 19, 2006

unplug all the drives
remove the ram
re-seat the video card
remove all other expansion cards

Still having problems?
posted by defcom1 at 4:17 PM on July 19, 2006

One more thing...I thought I remembered something like this happening to me, and it did. What fixed it was resetting the BIOS PRAM, or whatever they call it in PCs. It involved removing the clock battery, then holding down a nearby button on the motherboard. Check your mobo docs for details.
posted by trevyn at 4:17 PM on July 19, 2006

oh, try another video card.
posted by defcom1 at 4:18 PM on July 19, 2006

What trevyn is referring to is moving the CMOS jumper to the clear position for about 30 seconds, then moving it back, which does the same thing as removing the CMOS battery, without all the knuckle-scratching fun.
posted by cellphone at 4:20 PM on July 19, 2006 [1 favorite]

If you've got a modern P4 motherboard, you may need aux power supplied via the ATX12V connector (scroll down), normally a 4, 6 or 8 pin 2 row Molex connector that usually plugs in near the processor socket to deliver additional current for CPU fan and mainboard power regulator circuits.
posted by paulsc at 4:20 PM on July 19, 2006

Also, if you're using a 400w power supply with too many devices or too powerful of devices, it's not going to cut it, which is why you should list what components specifically are involved. That's just a guess on even the CD-ROM not opening despite being powered.
posted by cellphone at 4:21 PM on July 19, 2006

That worked. I had low hopes, but it booted. A winner is me! Thanks so much!
posted by Mayor Curley at 4:23 PM on July 19, 2006

For archival purposes, Mr Mayor, what worked?

And we're happy for your win.
posted by baylink at 5:14 PM on July 19, 2006

When I had a similar issue, a Port 80h card worked wonders for me. They're reasonably cheap and certainly less expensive than just buying a new motherboard and hoping everything will work out.
posted by adipocere at 5:31 PM on July 19, 2006

For archival purposes, Mr Mayor, what worked?

Moving the reset jumper for a minute and then trying again.
posted by Mayor Curley at 6:27 PM on July 19, 2006