Power Problem

gwave65

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Jul 23, 2005
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I'm a newb to this forum so I'm not sure if i'm posting in the right spot, sorry if i'm not. Whenever I press the power button on my PC, nothing happens except the CPU fan jumps a little. Here's what I've done so far:

-PC is plugged in. (duh)
-Replaced with known good POWER SUPPLY.
-Replaced with known good MOTHERBOARD.
-Replaced with known good CPU.
-Unplugged all non-essential components (fans, disk drives, lights, USB, memory).
-Removed mobo from case to make sure it wasn't shorting out on the case.

The only thing I haven't replaced is the case. Any ideas? Thanks,

Chad
 

fate

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Did you try reseating the original cpu? What do you mean by the cpu fan is jumping? Like running slow or it's hopping down your NB?

I wouldn't call memory non-essential :p
 

gwave65

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Well, non-essential that you don't need it to get power to the mobo and have fans start turning. Yes, i've replaced and reseated the cpu. The CPU fan will twitch a little when I hit the power button then stop. I had a gigabyte mobo that was doing the same thing so I sent it back for repair and bought a MSI refurb from NewEgg which did the same thing. I sent the MSI back to NewEgg and they returned it and it's still doing the same thing. The only conclusion I can come to is REFURBS SUCK!

<P ID="edit"><FONT SIZE=-1><EM>Edited by gwave65 on 07/23/05 01:24 PM.</EM></FONT></P>
 

alladinsane

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Did you use the same psu and cpu for all the mobos you tried? Did you try another cpu or another psu to see if those were the problems? I can't imagine that you got 3 bad mobos in a row even if they were refurbished.
 

gwave65

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The PSU was the first thing I tried. I bought a brand new one from Best Buy b/c we were in a pinch at the time, still did the same thing. That's when I knew my PSU was ok. I tried the same CPU that i'm using to type this message and it didn't work.
 

IasubtledaggerI

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this happened to me too. does the power supply come with a voltage display? if it does, you need to plug that in. well at least thats what fixed mine.
 

Crashman

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Former Staff
You replaced the board? It's probably shorted on the back side. Check for mounting points that are touching places that don't have holes. Removable mounting studs are called "standoffs".

Otherwise, you might have the power switch connected improperly, or a bad power switch. Power switches are "momemtary contact", you can do the same thing by touching the two power switch connector pins together with a screwdriver (to test for a bad switch).

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gwave65

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Oh, how I wish it were that simple. I've had this thing sitting outside the case on a anti-static bag and tried to powered it up. I don't think it's the switch because the CPU fan will move a little when I first click the power button. I think it may just be the PC from Hell and I'm starting to consider sending it back to the firey depths from which it came. Thanks for everyone's help.
 

Crashman

Polypheme
Former Staff
No, the fans are supposed to do that when you turn the power cord on (or plug it in, when the PSU has no switch for the cord). ATX systems ALWAYS have power running through the board, so that the power switch can operate.

So you'd get that little flick of the fans even if the power button was unhooked.

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gwave65

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I tried touching the two power switch pins together w/ a screwdriver but it just did the same thing. Just twitched the CPU fan a little.
 

Crashman

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Former Staff
Well, without a ground preventing it from booting, any other problem seems unlikely. Make sure the ATX12v connector is attached, but that normally results in a system that turns on but won't boot.

What video card are you using again?

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Crashman

Polypheme
Former Staff
Hmm.

Well, the problem you're having would normally indicate a power fault on the board. And the most common type of power fault is having the board shorted to the case on the back side.

One other thing: Make sure the BIOS jumper (CLR_RTC, CLR_CMOS, or similar label) is set to normal, not "clear".

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gwave65

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CMOS is set to normal and mobo is not touching case. I think I just got another flakey mobo.

*Note to self: Don't by any more flakey mobo's from NewEgg.

Thanks for all your help Crashman.