New build won't stay on

June 14, 2009 at 12:21:49
Specs: None
Just built my first: GigaByte GA-EX58-UD4P motherboard, i7-920 CPU, Corsair 750W power supply, Sythe Mugen 2 cooler. Won't POST. When press power button, CPU frequency LEDs light up, NB Phase LEDs light up, SB Voltage LED lights up, all three fans spin. Within one second, everything turns off. This happened with everything plugged in or nothing; I've unplugged everything except CPU, 24 & 8-pin power connections plus 3 fans. I turn on using power button on mother board.

The very first time I turned things on, everything worked (power came on and stayed on), except I got long + one or two short beeps and I never got video. Now just brief fans + leds, then turn off.


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June 14, 2009 at 13:05:16
I'm guessing you didn't benchtest your hardware before you installed it in the case? That was a huge you have no idea if the components even work properly or not. And there are numerous things that could have gone wrong within the case.

The following are the ONLY components you need to test the system:

- motherboard
- ONE stick of RAM
- power supply
- video card or onboard graphics (if you have onboard, use it)
- monitor
- keyboard

That's It! Everything else should be disconnected. If you're unable to boot & enter the BIOS, remove the board from the case & check for any unneeded motherboard standoffs shorting out the underside of the board. Also, double check that your HSF was installed correctly. If you didn't lock it down securely or used the wrong amount of thermal paste, it will prevent the system from booting.

Here's the thermal paste instructions...make sure to read the comment at the bottom right of the page:

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June 15, 2009 at 05:44:43
Thank you so much for responding. You can't imagine how relieved I feel.

I've removed everything and inspected the motherboard. I don't see any shorts. I did use 9 standoffs to hold the motherboard because there were 9 holes for screws. However, there were only four screws with motherboard, so I only used four screws. I am removing all standoffs except the four where I will actually use screws, as per your instructions.

I did not apply the thermal paste as described on the Arctic Silver site (I spread it out with a credit card), so I am in the process of removing the huge Mugen 2 cooler that I attached. That cooler required that I remove the cooler backplate from the back of my motherboard and replace it with a larger one supplied by Scythe. For testing purposes, I am going to install the smaller cooler that came with my i7 processor using the technique on the Arctic Silver site. That way, if the problem is due to the large Mugen backplate, this will eliminate that.

I do have one more bit of information for you. There are two connectors from the power supply to the motherboard: 24pin and 8pin. When I removed the 8 pin connector and only had the 24 pin connected and pressed the power on button, the motherboard did seem to power up (i.e. fans continued, led lights on motherboard continued) past the 1 second limit. I shut off the power after 2 seconds because I didn't know whether not having the 8-pin connector connected was bad. I also wanted to point out that although the Corsair 8-pin connector fits into the Gigabyte 8 pin sockets, the pattern of round and square pegs/holes are not the same. The socket has 4 square holes and the connector has only 2 square pegs. I don't know if this is significant or not. Do I need the 8-pin connector connected? Is the hole pattern mismatch important?

I'll report back when I have the cooler replaced and put together the minimum system as you suggest.

However, I really want to ask you what you mean by bench-testing the components. I didn't see any reference to this in the sites I looked at (PCMech, PCWorld video, Tom's hardware sites). Can't I go back and bench test them now? Or what should I have done for the next time?

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June 15, 2009 at 08:56:31
I've finished the list of things that you asked me to do. I have a system that only has following:
GigaByte GA-EX58-UD4P motherboard
i7-920 CPU with supplied cooler mounted; Arctic Silver applied per website
Corsair 750W power supply
BFG GTX280 video card
1 stick of OCZ 2GB DDR3 RAM in slot 1
monitor and USB keyboard
2 case fans and CPU fans plugged in
24pin and 8pin power cables plugged in
PCIE 8 pin plugged into video card
no other cables or wires
only 4 screws on 4 standoffs holding down mobo

I use a power switch on the mobo to power up

No change in behavior: when press power on, all fans turn and some leds light up and then power cuts immediately.

If I remove the 8pin power connector from power supply to mobo, system appears to power up fine, but I don't let it go longer than about 3 seconds before cutting power.

Please let me know how to bench test mobo before assembly.


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