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Rebuild computer wont power up

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17 replies

by eman220

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Basically, I went out and bought a new tower for my PC. About 3 years ago I gutted and rebuilt a new computer and now the new case is for that computer. I just hooked everything up in the case and when I hit the power button everything comes on for about 10 secs. then it shuts off... I'm very frustrated with this, any help is welcome.

17 replies

by rob miners

First thing to try is loosening the Screws that hold the Motherboard to the Case. They will only need a full turn. Reconnect the Power and turn it on. If it powers up shut it down and retighten the screws. They only need to be firm.

Make sure that there are no loose screws or other components inside the case. These can cause shorts and other serious problems with the PC.

Also check the power outlet that you are connected to by plugging in something else and turning it on.

A faulty (PSU) Power Supply Unit can also cause it. Fluctuating power or an underpowered PSU is not good for the Motherboard. You should be running 500-600 Watts. Try another one if available or replace it.

If it's none of the above try this Bench Test.

Carefully remove everything from the Motherboard. Remove the Motherboard and put it on an anti-static mat on a bench. Check the mounting stands and make sure that they line up with the holes on the Motherboard and they are all of the same height, so they are not shorting out the Motheboard. Remove the Power Supply if it is a known working one to test with. Remove the Heatsink and give it a good clean. Remove the CPU and reseat it. Reinstall the Heatsink remembering to use CPU grease. Reseat the RAM and test with one stick at a time. Connect a hard drive and the Video Card. Connect the Power supply to the Motherboard. You can use a flat blade Screwdriver to short the Power pins on the Motherboard if you haven't got a spare switch. Connect the Monitor and turn it on and see what happens. If it stars up add one Device at a time to test it.

Troubleshooting Flowchart
http://www.fixingmycomputer.com/flowcharts/boot-up-flowchart.html

by eman220

I actualy figured it out last night, my cpu fan connection wasnt in all the way, but then when i turned it on a screw fell into the PSU and blew it up.

I bought a 450W one and now it comes on but there is no input for my screen. I took out the graphics card, hooked the screen into the motherboard and all I get now is a black screen with a blinking cursor.

Now I think my PSU is not stong enough (the old one was a 500W) because the LED that says the hard drives are working will come on for a second then it will flicker and go out.

by slayer_

Are you running a high end video card or something?

CD's, HDD's, and processors don't take up much power (In comparason), a 250watt PSU would be fine if a system did not have a video card.

by eman220

I got a BFG GS-450, and I'm going over to my neighbors house to double check the Graphics card

by computechdan

perhaps the power button is sticking

try connecting the reset button wire to the power on connector on mainboard

by eman220

I checked that first, used my fluke meter from work, shorts when I push the button.

by ---tk---

this might sound stupid but did you put enough thermal grease between the CPU and heat sync?

It amazes me how fast a CPU can heat up with out it... that would be enough time for it to heat up and then the BIOS protects the system by turning off the PC....

by slayer_

Every time i've blown a video card, that is the exact thing it does to me, boots up, 10 seconds laters, the machine shuts down inexplicably. 1 out of 100 times it might actually get into windows and will suddenly turn off again.

I've blown 3 video cards and each time that was the symptoms.

by eman220

Well it was high end about 3 years ago, but off the top my head (I'm at work right now) I know it's a Nvidea, my Motherboard is an ASUS (not sure of model), proc. is AMD (not sure of model but it is a dual core 2.8 GHz on each), 2 Hard Drives (and 160GB, and a 1TB), 4X120mm fans, and one 200mm fan, I also have a sound card, but I took it out when doing some testing so it's not the issue. I don't think the graphics card is fried because I took it out and looked it over, and also smelled every inch for burned electronics, I know the smell very well. The mother board might be fried though, I was hoping it wasn't... I'm just going to tear it down to just the CPU, RAM, and PSU.

by slayer_

Try reseting your CMOS, move your jumper to the correct position, press the power button, let it run for a moment, shut it back down and move the jumper back tot he proper spot.

The jumper should be located close to the battery.

by eman220

I came home, booted up the computer, and magically it started working. I think / know the Graphics card is fried, it just sucks that I don't have the money to replace it with the same thing right now, might go ahead and get the BFG NVIDEA GeForce 8400 GS, or a ATI Radeon HD 4350

by rob miners

to try your graphics card in just to be sure. The Big Bang may have taken out the slot. Also was the new PSU an el cheepo or did it cost a bit like an Antec would.

by eman220

Roger that, I'll probly be testing it at work on one of our workstations. just hooked it back up too my computer and noticed there is a red fault light on the board... I deff. don't want to replace this damn thing

by slayer_

My best guess is it is because they often run hot. Graphics cards don't have a long life. Not in this day and age anyways.

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