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Bad PSU or am I out of luck?

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October 16, 2010 12:53:11 AM

Hey.

When I built my PC in early September, it worked perfectly fine. I noticed that I should move my video card to the top PCI-E slot to move it from the PSU's fan since they were so close. Anyways, I do that, put my PC back in, plug my mouse in, but I noticed that my mouse's LED was on even though my computer wasn't. I didn't think much and turned on my PC. I got to the BIOS screen but it took twice as long to get past. After it got past, it went to load the OS from my HDD, but it stayed there for about a minute before saying that it could not find the HDD. I turned off my PC, opened it up and checked to see if everything was plugged in, they were.

I reseated all the HDD wires and brought it back and fired it up. Same thing. I also noticed my keyboard's LEDs weren't lighting up, and I couldn't access the BIOS. Figuring this was a mobo error, I sent it back. Got it back today, put everything together and thought it would work. Sadly, I was wrong and it doesn't even turn on. When I opened it I noticed that the video cards fan twitches if I hit the power button - the case fans do sometimes as well, but the CPU's fan doesn't. Now I think either the PSU isn't working, or the CPU's fan isn't and the PC doesn't turn on to avoid killing my CPU.

If you need my build, this is it:
Gigabyte GA-P55A-UD3 - mobo
WD 7200RPM 1TB - HDD
XFX HD 5850 - Video card
Intel i5 750 - CPU
Antec True Power 750 Watt - psu
HAF 922 - case
Razer Death Adder - mouse
Logitech G15 - keyboard

The keyboard and mouse work, I tried it on both of my laptops. I don't know anyone with a pc that I can try my PSU on, everyone I knew has a laptop or really old desktop.

Sorry for the long read.

More about : bad psu luck

a c 713 ) Power supply
October 16, 2010 1:05:31 AM

Did you plug in the CPU power connector?
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October 16, 2010 1:08:32 AM

Yes, I checked the connector for the CPU and the fan aswell.
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Related resources
October 16, 2010 1:17:17 AM

It's possible but when i called they said they just got finished testing, I'll check the guide and see if it helps.
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October 16, 2010 1:24:27 AM

Okay, I read it and I already did everything it said, except for the trouble shooting of the RAM. I don't think the RAM is a problem. I'm sure it's either the PSU or fan. The only reason I think it's the cpu fan is because it doesn't twitch like the rest of the fans.
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a c 713 ) Power supply
October 16, 2010 1:27:34 AM

It should still boot even if the fan does not spin up if that is the only problem.
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a b ) Power supply
October 16, 2010 1:31:26 AM

The first thing that you should try is to reset the CMOS memory by DISCONECTING THE POWER and momentarily moving the clear CMOS link.
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October 16, 2010 1:31:38 AM

Then I guess the PSU is bad. Would I have to get that volt meter thing to check? Or is there another way? I think that my mobo has a fail-safe function that shuts down the PC if the fans fail, that's why I though it could be the cpu.
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October 16, 2010 1:35:14 AM

Didn't try the CMO's, I'll try it when my brother is finished taking a shower, my bathroom is the only place without carpets and I don't want to run the risk of static shock, I don't want to go through 2 RMA's.
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October 16, 2010 2:55:32 AM

Okay, I tried the reseating of the RAM and the CMOs battery reseating, neither worked. I guess it's RMA on this one, thanks anyways guys.
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a c 144 ) Power supply
October 16, 2010 5:10:39 AM

Don't know.

Work through our standard checklist and troubleshooting thread:
http://www.tomshardware.com/forum/261145-31-read-postin...
I mean work through, not just read over it. We spent a lot of time on this. It should find most of the problems.

If not, continue.

I have tested the following beep patterns on Gigabyte, eVGA, and ECS motherboards. Other BIOS' may be different.

Breadboard - that will help isolate any kind of case problem you might have.
http://www.tomshardware.com/forum/262730-31-breadboardi...

Breadboard with just motherboard, CPU & HSF, case speaker, and PSU.

Make sure you plug the CPU power cable in. The system will not boot without it.

I always breadboard a new build. It takes only a few minutes, and you know you are putting good parts in the case.

You can turn on the PC by momentarily shorting the two pins that the case power switch goes to. You should hear a series of long, single beeps indicating memory problems. Silence indicates a problem with (in most likely order) the PSU, motherboard, or CPU. Remember, at this time, you do not have a graphics card installed so the load on your PSU will be reduced.

If no beeps:
Running fans and drives and motherboard LED's do not necessarily indicate a good PSU. In the absence of a single short beep, they also do not indicate that the system is booting.

At this point, you can sort of check the PSU. Try to borrow a known good PSU of around 550 - 600 watts. That will power just about any system with a single GPU. If you cannot do that, use a DMM to measure the voltages. Measure between the colored wires and either chassis ground or the black wires. Yellow wires should be 12 volts. Red wires: +5 volts, orange wires: +3.3 volts, blue wire : -12 volts, violet wire: 5 volts always on. Tolerances are +/- 5% except for the -12 volts which is +/- 10%.

The gray wire is really important. It should go from 0 to +5 volts when you turn the PSU on with the case switch. CPU needs this signal to boot.

You can turn on the PSU by completely disconnecting the PSU and using a paperclip or jumper wire to short the green wire to one of the neighboring black wires.
http://www.youtube.com/watch?v=5FWXgQSokF4&feature=yout...

This checks the PSU under no load conditions, so it is not completely reliable. But if it can not pass this, it is dead. Then repeat the checks with the PSU plugged into the computer to put a load on the PSU.

If the system beeps:
If it looks like the PSU is good, install a memory stick. Boot. Beep pattern should change to one long and several short beeps indicating a missing graphics card.

This will be a little different if you have integrated graphics.

Silence or long single beeps indicate a problem with the memory.

Insert the video card and connect any necessary PCIe power connectors. Boot. At this point, the system should POST successfully (a single short beep). Notice that you do not need keyboard, mouse, monitor, or drives to successfully POST.

Now start connecting the rest of the devices starting with the monitor, then keyboard and mouse, then the rest of the devices, testing after each step. It's possible that you can pass the POST with a defective video card. The POST routines can only check the video interface. It cannot check the internal parts of the video card.
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October 17, 2010 3:01:14 PM

Thanks bro, the green black paperclip thing worked, I got an email from an Antec customer support agent telling me to try it, and it worked. It basically jump-started my PC back to life, however there is one problem, when I turn on my PC, it will turn on, get to "Loading Operating System..." then shut off. Two seconds later it will turn on by itself and and work perfectly fine. It does this every time I turn it on. Any ideas?
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