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New PC built wont power on.

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  • Homebuilt
  • Cases
  • Power
  • Systems
Last response: in Systems
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January 6, 2011 5:43:34 PM

Hello i just(attempted) to build my first home PC. I have everything together and in the case with the power supply hooked up and all the cables attached but when i hit my power on my case nothing turns on. The 24 pin power is connected for MB power, the 8 pin power in connected for the CPU, the CPU fan is attached to the mobo(via 4 pin labeled CPU_FAN) the disc drive/HD are both connected to both power supply and mobo and i connected all the case connections to the mobo(pwrsw, resetsw, LED, USB, IE1394_1) The little green LED on the mobo is lit up so im assuming there is power. When i hit my power button on my case nothing at all happens, no fans whirl, no noise, no beeps nothing happens at all.

Asus M4a88T-V Evo/USB3
AMD Phenom II X4 3.4 965BE
Gskill Ripjaw DDR3 1333
WD Caviar Black
Corsair 850W PSU

P.S this is my first ever build.

More about : built wont power

a b B Homebuilt system
January 6, 2011 6:02:41 PM

http://www.tomshardware.com/forum/261145-31-perform-ste...

looks like you covered a lot of what is suggested in the above link, though I might try taking a look at section 17... if you have all of the front panel connection wiring correct you may have a post in the wrong place or something grounded causing a short in the system.
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January 6, 2011 6:11:33 PM

I would agree, double check the leads from the front of the case...

They are correct, try re-seating the CPU/grease/Fan, re-seat the RAM
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a c 122 B Homebuilt system
January 6, 2011 6:15:43 PM

Work systematically through our standard checklist and troubleshooting thread (the one that eilavatar linked to):
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, try this.
I have tested the following beep patterns on Gigabyte, eVGA, and ECS motherboards. Other BIOS' may be different, but they all use a single short beep for a successful POST.

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 once you are finished.

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...

A way that might be easier is to use the main power plug. Working from the back of the plug where the wires come out, use a bare paperclip to short between the green wire and one of the neighboring black wires. That will do the same thing with an installed PSU. It is also an easy way to bypass a questionable case power switch.

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.

Silence, long single beeps, or series of short beeps indicate a problem with the memory. If you get short beeps verify that the memory is in the appropriate motherboard slots.

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.
At this point, if the system doesn't work, it's either the video card or an inadequate PSU. Or rarely - the motherboard's PCIe interface.

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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January 6, 2011 6:33:15 PM

One more thing to try, pull the power cord from the PSU, push the power button (2 sec), and use the jumper to "Clear RTC RAM" (resetting the BIOS). Place the jumper back in the correct spot, plug the power back in... and try booting up.
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January 6, 2011 6:48:50 PM

I just ordered a system speaker so i can hear the beeps, im slowly working my way through the steps right now making sure everything is fully seated rechecked the front connectors made sure i dont have any extra stand offs or screws in the case, no wires are touching the Mobo. I also rechecked the CPU/heatsink fan it is all installed correctly and the CPU fan is plugged in. Thank you all for your quick replies and i will let you know how its coming.

One quick question, thers a 3 pin connector on my Mobo labeled PWR_FAN do i need to use this for anything? its right next to the RAM slots.
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January 6, 2011 7:31:01 PM

Not really, in all reality you don't have to use any of those connectors... Some people say don't use them at all, and just run right to the PSU... That way they are always running at a 100% and the motherboard doesn't have to use its own power...

Did you try resetting the BIOS, with the jumper? I have had to do that on some new builds...
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January 6, 2011 7:38:38 PM

oh ok i did not try resetting the bios with the jumped i went down the list (from lamp testing the socket in the wall all the way to step 18.) And it turns out that i had to switch around the power/reset switch connectors i put the reset one where the power one SHOULD go and it booted up and am now installing win 7. i double checked both my Mobo manual and the case manual to make sure i had everything in the right spot i then checked the colors of the wires and the label on the connectors my buddy has the same case as me so i called him up turns out my pwr_swch wire was labeled wrong :( 
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January 6, 2011 7:46:48 PM

Good deal! Have fun!! :) 

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