Sign in with
Sign up | Sign in
Your question

Motherboard/Case Not Turning On

Last response: in Systems
Share
September 6, 2008 8:26:12 PM

Hi all,

I recently bought all the parts for my new computer and put everything together, but when I press the power button, nothing happens. No beep, no LED light, nothing. Here are my specs.

GIGABYTE GA-EP45-DS3L LGA 775 Intel P45 ATX Intel Motherboard
CORSAIR CMPSU-650TX 650W
RADEON HD 4870
OCZ 4GB (2 x 2GB) 240-Pin DDR2 SDRAM DDR2 800
Intel Core 2 Quad Q6600 Kentsfield 2.4GHz LGA 775
Western Digital Caviar SE16 WD6400AAKS 640GB 7200 RPM SATA HD
COOLER MASTER Centurion 5

There are two green wires that the Centurion 5 case has, labeled (+) and (-). I believe those are for Power LED. But the Power LED header on the motherboard has three pins. I don't know what orientation the plugs go in (the manual doesn't really make it clear). Could this be the reason my computer won't start up? I'm pretty sure I have all the other front panel headers hooked up correctly. Thanks in advance.
September 6, 2008 8:28:20 PM

Try to short-circuit with some metal clips pins that are used for power button on mobo. If it boots up maybe your button has problem.
September 6, 2008 8:30:37 PM

Ok wait I'll see the manual
Related resources
September 6, 2008 8:37:37 PM

I see mobo has 3 pins for led, + is the lowest one on the mobo at the edge and the other 2 are -
a c 83 B Homebuilt system
September 6, 2008 9:28:10 PM

If you plug the power led pins in the wrong way, the power led lights will just not work. It will not be the cause of your system not powering up.
1) is the psu plugged in?
2) is the power switch on the psu turned on?
3) are all the power leads securely plugged in to the motherboard?
4) is the cpu fan plugged in?
--------------------------
Next, take the motherboard out of the case, and put it on some cardboard.
Install only the minimum required to post.
that is:
psu,
cpu and cooler,
one stick of memory,
vga card and monitor,
keyboard,
the power button lead from the case.(you could also short the power pins with a screwdriver to turn it on)
the idea is to eliminate the possibility of a case short.
September 7, 2008 12:04:54 AM

After a few hours of messing around with the frontal panel headers, I came to the conclusion that the color convention of the case does not match that of the motherboard. I randomly plugged the HDD LED into an incorrect header and found that a blue LED light was turned on in the front panel. I was still not able to get the computer to boot up, though. Since I did get an LED light working, I think it's safe to assume that the PSU is working, right?

I also tried a different case and was unable to get the computer to boot up. Could it be a motherboard problem?

The PSU is plugged in, and the power switch on the PSU is turned on. All the power leads, to the best of my knowledge, are plugged securely into the motherboard. The CPU fan is plugged in to the correct header.

I will try geofelt's minimalist approach next, and if that doesn't work, I'll have to take it to a repair shop.
September 7, 2008 2:40:19 AM

Update: I tried taking the motherboard out of the case and powering just the 24-pin power connector, the 4-pin 12V connector, and the video card. I still couldn't get the thing to power on. After that, I removed the video card and got the same result. This was while using one stick of memory. I also tried shorting the power with a screwdriver, no use.

Could it be that my motherboard is defective?
a c 83 B Homebuilt system
September 7, 2008 8:52:21 PM

I would suspect a defective motherboard at this point, but it could be anything.
New parts are rarely defective. Usually it is something simple.
Try using the other stick of ram, and in different slots.
Are there two pci-e power connectors plugged into the 4870?
Is the monitor powered, and turned on?
Is the monitor cable good?
September 8, 2008 8:17:26 PM

Hmm... I'll give those a shot.

When I turn on my power supply, should the fan at the bottom of the PSU be running? Because if so, then I would suspect my power supply is dead, because the thing doesn't do anything at all when I switch it on.
a c 83 B Homebuilt system
September 8, 2008 8:27:17 PM

The fan on the psu may not spin up until there is enough load to heat it up.
September 9, 2008 3:19:28 PM

Update: It turns out the problem WAS something simple. I didn't install spacers underneath the motherboard, meaning the entire bottom portion of the motherboard was in contact with the metal case. My computer is working just fine now.

Thank you for all your help and assistance. I really do appreciate it. :) 
!