Solved Computer not powering up

[alumahai]

I just bought a few upgrades for my computer, and was really excited to get to work today. After a few hours of fiddling with small problems, I finally got everything together and tried starting up my computer... to no avail.

I purchased a new case, a new motherboard, and a new heatsink.

I swapped over my i5-760 processor from my old computer, got the new heat sink on just fine, and dropped the motherboard into the case. The old 460 watt power supply dropped in just fine, except the cpu power only had the 4 pins, going into the 8 pin on on the board. I assumed this would work, as the slot on the board only has the one clip, and it fit just fine. the hdd and dvd drives both went in without a hitch, but I had a little bit of trouble getting my Nvidia 550 ti in, as the metal seemed a little bit warped in the back. Never the less, it wound up fine, except for a tight fit.

Here comes the biggest problem. I plugged in the power to the system, flipped the psu power switch on, and pressed the power button, only for nothing to happen. no lights, no fans, no nothing.
Is my board bad? What to do? please help. I have to finish my data structures program tomorrow, and my computer is not cooperating.

I figure since everything worked before, its either the case or the motherboard.
or the psu no longer supplies enough power...

if it helps at all, the motherboard is an msi p55-gd80

 

[Dave Atkin]

Hello,

"The old 460 watt power supply dropped in just fine, except the cpu power only had the 4 pins, going into the 8 pin on on the board."

What do you mean by this? The motherboard will need all the connectors.

Also, make sure that your power button is properly connected to the motherboard.



Dave

 

[chris1neji]

I remember when i did upgrades to my computer, i though i had plug in my motherboard power connecters all the way in. It would turn on for a split second like it wanted to turn on. But it didn't. It was well inserted but not all the way in. Any chance you can upload a picture so we can know what this 8 pin are.

I would uninstall all other hardware and test one thing at a time and slowly adding more components on.

 

[alumahai]

PERFORM THESE STEPS before posting about POST/boot/no video problems! - New-System-Build - Homebuilt-Systems < this

 

[bobkn]

Most motherboards have LEDs that light to show power to the board.

Got one? Does it light?

 

[alumahai]

Sorry if I sound a little angry, but I just took everything apart and put it all back together a second time, only to have it still do nothing.

Most motherboards have LEDs that light to show power to the board.

Got one? Does it light?

No. I repeat, no fans, no lights, nothing. Its as if it isn't plugged in to the wall.

 

[jlhawn]

your mother board has to have the 8 pin power connector so you need a new psu.
after you get a new psu the cap on the mother boards 8 pin connector can be removed for your 8 pin plug. it is your cpu that needs this 8 pin power so as long as the cpu is not getting power nothing will happen when you push the power button

 

[alumahai]

I really hope that's the case, because my new 750 watt is set to come in tomorrow. If that doesn't fix it, what is there to do? i can only think of moving everything back to the old motherboard, and trying that with the new case. If that works, obviously the motherboard is broken, and I need to return it. I mean, I doubt that its just something wrong with the case connecting to the motherboard, but...

 

[bobkn]

Sorry if I sound a little angry, but I just took everything apart and put it all back together a second time, only to have it still do nothing.

Most motherboards have LEDs that light to show power to the board.

Got one? Does it light?

No. I repeat, no fans, no lights, nothing. Its as if it isn't plugged in to the wall.

I checked the manual for your board. I see that it has a lot more LEDs than a simple board. Illuminated onboard power switch as well.

While the board has an 8 pin ATX12V connector, I'd expect it to be able to boot with a 4 pin one. It may have come with a plastic cap to assure that you plugged the 4 pin into the correct side of the 8 pin socket. (If you engaged the clip, it's on the correct side.) Even if you really need the full 8 pin +12V connector, I'd still expect some of the LEDs to light when you apply power to the board.

As to why the board is behaving as if it is getting no power, I can't guess. A standard suggestion is to put a minimal system together outside the case. That would be the board, CPU (w/cooler), graphics card, one RAM stick (in DIMM1 slot, which is the second slot from the CPU), and a keyboard. The point isn't to run the PC, but simply to see whether you can get into the BIOS. What this mainly checks for is electrical shorts to the case.

Good luck.

 

[jlhawn]

I really hope that's the case, because my new 750 watt is set to come in tomorrow. If that doesn't fix it, what is there to do? i can only think of moving everything back to the old motherboard, and trying that with the new case. If that works, obviously the motherboard is broken, and I need to return it. I mean, I doubt that its just something wrong with the case connecting to the motherboard, but...

due to policy i cannot post who i work for but i am 99% positive that you must use an 8 pin plug for your cpu on that board. if it does not correct the problem then it is a bad mother board but since your computer is not in front of me i can't perform any diagnostics as it's hard to troubleshoot over a forum. my asus board had a plastic cap over 4 of the 8 pins also but the manual stated that if i did not use an 8 pin power connector it would not boot up. why they have the cap on there? i don't know.

 

[Dave Atkin]

I am also confident that it is the PSU and the connections. Best of luck! Let us know how you get on.


Dave

 

[alumahai]

Yup. It was the 4pin vs 8 pins. It's working fine now. Thanks, guys.

 

[bobkn]

Yup. It was the 4pin vs 8 pins. It's working fine now. Thanks, guys.

That's a surprise. I would have made a small bet (5¢) that you would have gotten lights on the MB even if it wouldn't boot reliably.

Good to know, though.