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Home build won't power - what have I done!?

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Last response: in Systems
July 31, 2008 6:00:19 PM

I recently put together the following

Asus 790fx
AMD 9950 Black @ 2.6 ghz
Corsair 4gb(2x2gb) 1066ghz Dominator
Thermaltake 600w Purepower

This isn't my first build but I am no expert. However, it won't power on. I checked the PSU and the switch on the case with another computer, and both work fine. Is my power supply to wimpy? Or do I have a hardware failure? From what I know it's gotta be either the mobo or processor, and the mobo has the green standby light which reduces my suspicion of it. Can anyone tell me what I'm doing wrong here?

More about : home build power

July 31, 2008 6:08:12 PM

what HD are you using?
July 31, 2008 6:09:33 PM

I have the hard drive and everything else unpowered atm. I just have it down to the processor, memory and motherboard.
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July 31, 2008 6:13:11 PM

Did you connect the 4 pin power supply connector?
What is your video card?
Clear the bios.
July 31, 2008 6:19:48 PM

Its not connected atm
Uh like do an nvram clear? I can try that, might work. Its not even powering on tho, like i press the switch and nothing, no proc fan, no PSU fan, none of the fans do anything
July 31, 2008 6:28:23 PM

evongugg said:
Did you connect the 4 pin power supply connector?
What is your video card?
Clear the bios.

take a breath

4 pin to the aux cpu connector, up near the cpu? plugged in?
July 31, 2008 6:34:16 PM

yup, 4 pin is connected
July 31, 2008 6:34:44 PM

did the ram automatically 'click' when u put it in?
July 31, 2008 6:37:54 PM

yes sir, it is well seated

and cleared teh bios, no change =(
July 31, 2008 6:39:25 PM

did u try taking a hammer and hitting ur PSU very hard with it?
*note* one well placed hit should be sufficient
July 31, 2008 6:50:00 PM

Is the power switch connected properly? Also check if the motherboard is actually getting power. If the LED comes on then motherboard is getting power.

Side note: Did you use the standoffs? Forgetting these can cause no power on sometimes.
July 31, 2008 6:50:51 PM

If some pins are plugged in the wrong place, the mobo won't [post.
July 31, 2008 6:53:21 PM

ha not yet, i actually tried the PSU/case power switch on another system i had lying around, the other system was able to power. So i dont believe it to be the power supply or case switch
July 31, 2008 6:58:18 PM

Yah the motherboard standby LED turns on. And yes the power switch is connected, I actually tried to use a power switch from another case and that didnt seem to work either. Im assuming the colored wire is the voltage and the white one is the ground, and I have that plugged in properly.

Shadowthor: Which pins? I can definitely double check.
July 31, 2008 7:05:21 PM

Did you mount the motherboard directly to the case, or did you use brass standoffs?
July 31, 2008 7:12:32 PM

just short the power pins on the mobo with a scredriver, takes any switch or reset switch problems out of picture
July 31, 2008 7:14:26 PM

Take the motherboard and PSU out of the case, put them on an antistatic bag and jump the power pin with a screw driver. If it doesnt boot, reseat the CPU and verify it was installed correctly, if not, something is bad- CPU, MB, or PSU. If you take out the ram and the board doesnt beep then the board or CPU is shot
July 31, 2008 7:15:53 PM

Argh! northerdude you took the words right out of my mouth! Good call.

That is my suspicion as well. Sometimes the diagram for where the PWR, IDE, RESET, etc leads are plugged into the Mobo can be misleading. I would double and tripple check that they are plugged into the right ones. I have been known to make this mistake during this phase of installation due to my overwhelming desire to complete a new system build.
July 31, 2008 7:31:16 PM

ya it doesnt do anything when i dont have ram in there, just that Green light. i tried the case switch on another mobo and it worked fine. i also tried moving the switch connector to a few different configurations on the pins, and that didnt seem to make any difference either. is there any way to tell whether its the mobo or processor or should i just replace them both. i did try shorting the pins with a screwdriver but im not sure the screwdriver im using is conductive =/.

and yes i am using the little riser screws, though i only have about 5 or 6 screws in the mb.
July 31, 2008 7:35:18 PM

Check yer leads from the front of the case. If you just matched colors, you may have put them in wrong. Check yer manual and make sure you put the right ones int he right places and make sure the plus and minuses are correct as well.

I did this with my first build too and finally figured it out. There were red and orange cables and pins, but the orange went with the red and red with orange. Great how that works, but needless to say i consulted by instruction booklet and solved the problem.
July 31, 2008 8:24:51 PM

Send it to me and I'll trade it for a working Pentium 4 dell :) 


July 31, 2008 8:42:51 PM

have you checked the fuse? It is a very small diode located close to
your power to mobo connector.....
at least most of mine are....
Ya gotta love this micro-technology that makes everything so small
that you need a magnifying glass and directions to find anything.
Most electronic circuits and boards today do in fact have fuses, they are
just micro'ed.
July 31, 2008 9:03:18 PM

Sounds like dead mo/bo
July 31, 2008 9:34:16 PM

I cant find a fuse at all, what does it look like exactly? I see a few things surrounding that, but none looking like a typical fuse
July 31, 2008 9:59:26 PM

The fuse would look like a small micro diode hard soldered between the
main power junctions...located at or around the power connector on the
mobo.... it may even be blinking, glowing green, or red....or just may display
an open circuit break if it is blown bad enough.
Either way, if it is is a dead mobo and should be replaced.
That is, the mobo replaced....not the fuse.

good luck
July 31, 2008 10:14:09 PM

If you really want to bother with the fuses, they are surface mounted, usually very flat. But sometimes they are tiny retangualr box shapes (but you wont be able to tell if they are surface mounted capactiors), the flat ones are usually green. the boxs one white or clearish white. You need a multimeter to tell if they are bad.

Oh, did I mention, you cant change them?

The only thing I can recommend you do is:

1. MAKE SURE YOUR CLEAR CMOS JUMPER IS IN THE RIGHT POSITION. Wont do anything at all if its not. motherboard will act exactly like it is if the cmos jumper is in the wrong postion. move it over and hit the power switch just in case you have it backwards. its the first blue one I believe above your Frontpanel header.

2. If that dont work, do the screw driver trick again. remove all of your front panel wires. Short out all the pins group togther that the power switch, hard drive led, power led, and reset switch connect too. do it in all directions, side to side and up to down (no diagonals, but diaganols wont hurt). Dont worry, you wont fry anthing (unless you strike the screw driver somewhere else other than those pins. use a butter knife if your not sure you have a metal screwdriver ( :pfff:  ). I believe that ASUS board has a little plastic connector that you put your front panel connectors on, then you put that assembly on the motherboard header. If so, be sure your using that.

3. If you have another power suppy handy, try it. Not all PSU and motherboards get along. Dont worry if its a small one, just as long as its more than 250watts. (this is just for testing)

4. Pull your CPU. Turn it around, and in good light, make sure you dont have ANY bent pins. If the cpu didnt literaly drop in (if you had to push at all) you screwed it up. If there is no bent pins, Put it back in after lining it up correctly, PUSH somewhat on the center of it before you lock it down with the lever. reapply thermal paste if you have it sparringly (after cleaning the old stuff off). if you dont have thermal paste handy, just leave the old stuff there and reapply the thermal paste if you get it working.

Other than that, send both the processor and motherboard to newegg, and get another pair

July 31, 2008 11:58:49 PM

Oh, and I think that mainboard can take an 8 pin cpu power connector. Take the 4 pin out, take off the paper thats covering the other four pins, and try your 8 pin CPU connector that your power supply has

August 1, 2008 12:32:07 AM

ya, i did that, i think im gonna start RMAing parts, and try to figure out whats going on. thanks for all the help!
August 1, 2008 1:16:26 AM

I had a friend that had a ps with 2 4 pin connectors, her board would not post either, but she plugged in the other 4 pin by accident and it worked fine.