Computer Help forum


Help Needed... New build and PC won't boot up??

by markeyd / May 23, 2013 7:11 PM PDT

Motherboard-Gigibyte GA-Z77X-UD5H
CPU-Intel Core i7-3770
Ram-Corsair Vengeance 32GB (4x8GB) DDR3 1600 MHz
PSU-Corsair TX 650 M
Hard Drives-SanDisk Extreme SSD 240 GB SATA 6.0 Gb-s 2.5-Inch Solid State Drive
Seagate Barracuda 1 TB 7200RPM SATA 32 MB Cache 3.5-Inch
Case-Corsair Carbide 500R

Hey guys,
I'm a fairly experienced builder. This is my sixth build so far but this problem has my head wrecked. Just cant figure it out.
I've just built this PC with all new components and when I power on all fans spin and BIOS light on motherboard comes on but only for about 2 seconds. After that the BIOS light goes off and all fans including PSU fan stop spinning. Then after about 4 seconds the BIOS light comes back on and all fans spin again for another 2 seconds and then go back off and everything comes back on again. This sequence keeps repeating itself over and over.
I've ruled out the PSU as I've replaced it with a working one from another machine and still have same problem.
The motherboard has 2 BIOS's a main and a backup with a switch to choose which one to boot from. I've tried both and still the same problem. I've also cleared the cmos and tried only 1 stick of ram but still no joy.
I'm guessing it's a motherboard problem or perhaps a faulty cpu.
Any advise from you guys would be most welcome as I'm pulling my hair out now at this stage.
Thanks in advance

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All Answers

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Cardboard time
by Bob__B / May 23, 2013 11:49 PM PDT

On a piece of cardboard.

Power it up.
If it does not power up your down to 3 parts.

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New PC in a power up loop
by pauly1651 / May 24, 2013 10:46 AM PDT

This sounds to me like a power problem.
Just because you used another PSU from a working machine, doesn't mean that is not the problem.
If you have a way to actually test the PSU, then do that. Testers are easy to get, and are worth the low cost. Either that or get another, new PSU, and make SURE you have all wires and cables connected right, then start it up again.
Power loops are usually a clear sign of faulty or bad power.

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Not the power supply
by mjd420nova / May 24, 2013 11:16 AM PDT

That would have been my first guess too. The next point to look at would be the CPU, it's seating in the socket, the heatsink, and its compound squeezed between the fan and the chip. There is also a temperature sensor in the chip that would create that 3 to 4 second delay in the shutdown if a fault is sensed. I suspect the compound has failed or was improperly applied, something to keep that heat from getting excessive and shutting the power supply down.

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Sounds like Power supply not large enough
by mickgrace / May 24, 2013 2:00 PM PDT

Have you tried another larger power supply as it sounds like the power supply could be turning on and off.

It could be due to the power supply being shorted or overloaded and there is a short in the system somewhere external to the power supply. This then causes the power supply to switch off automatically and back on again as the power supply is connected to the mains and has not been shut off in a way that it normally shuts down.

Is the power supply the correct wattage for all the stuff you are trying to run. Remove all unnecessary cards and try to get the PC to run with the bare minimum to get the PC to run. It is very important to have a large enough power supply capable of running everything with 40 to 50 percent extra wattage for new components in the future.
If you get it running on the bare minimum requirements you then replace the extra cards one at a locate the problem.

Is the motherboard earthed properly and running on the correct DC voltage.

I have not built computers for awhile now as have moved to notebooks, but a few years back we used to get beeps on startup to tell us the computer was booting up correctly, and if we had a problem you would listen to the beep sequence on boot up and you would look up a chart from the bios manufacturer, and correspond the beeps sequence and it would give you an idea where the fault was.

I hope some of what I have said helps, because I know what you are going through. Once you find out what the problem is let everyone know and put it down to an experience with a sharp learning curve.

Best of luck,


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Still no joy
by markeyd / May 24, 2013 9:40 PM PDT

Thanks everyone for you suggestions. I've tried Bob b's suggestion, taking the board out and putting it on cardboard with just cpu, hsf, psu and still the same problem. I managed to get my hands on some new ram sticks aswell which didn't help. The psu I used as a replacement works perfectly and I also put the psu off this build into another machine and it works fine in there too. I dont have a spare cpu unfortunately to test on the board but I did reseat it and blow out the socket with compressed air. So at this stage I'm thinking it has to be either cpu or mboard. But somethings telling me it's the mboard.
Pauly1651 I agree with you that it sounds like a power problem but as I've said I've ruled out the psu so I'm thinking maybe there's a short in the mboard circuit itself perhaps. The system gets to the exact same point each time, the Bios led on the board comes on for 2 seconds before it shuts off. It's like whatever the board needs to do next is causing a short somehow and also theres a little digital display thing on the board which gives out a number reading for error reports but this just flickers before it dies so yeah it sounds like a short circuit. It's a brand new board I bought online and it's under warranty so I might just chance my arm returning it as faulty hope they test it and if I'm right send me a replacement one.
Any other suggestions ??

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Check BIOS version on box
by samkh / May 24, 2013 10:22 PM PDT
In reply to: Still no joy

Does it support 3770?

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Boot system
by olibener / May 24, 2013 9:47 PM PDT

Had similar issue with my Gigabyte MB which would not boot up. Gigabyte suggested many ideas which are common, but the one that worked. Take the battery out of the MB, wait 15 minutes, and then replace. Computer booted up on first try and continued Windows 7 installation.

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Thanks guys
by markeyd / May 24, 2013 11:00 PM PDT
In reply to: Boot system

Yes it does support 3770 samkh
I did take the bttery out but not for 15 minutes so I'll try that and see if it works

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Back to basics
by Willy / May 24, 2013 11:53 PM PDT
In reply to: Thanks guys

Sine it tries to reboot, that suggests a bios action. if you ever get to settle, enter the bios and select don't reboot upon error status. Make it a never or stop upon error status, so it won't reboot. As already stated, make this a minimum system, you don't need any storage media attached, not even the cpu. However, be sure any speaker is working to announce any error beeps etc., and it should beep away with no cpu, but it should also remain ON for sometime or error out. Install cpu(check it) and see if it varies and what the display shows if anything. Otherwise, if nothing seems to work, return the mtrbd., as I believe that's the crux of your problem. BTW, how are you loading the OS, I see no CD/DVD drive listed from your OP?

tada -----Willy Happy

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returning motherboard
by markeyd / May 25, 2013 5:08 AM PDT
In reply to: Back to basics

Took battery out of mboard for 20 minutes and still no joy. Also powered up board without cpu or ram or anything else attached and it behaves the exact same way so I think at this stage now there's nothing else I can do. I'm returning the board as faulty.
Willy, I didn't bother list my CD/DVD drive. This computer is going to be a Hackintosh which I'll be using for music production only and I'll be intalling OSX Mountain Lion from a USB Flash Drive. That is if I can get the bloody thing to eventually boot up.............. Lol.

Thanks everyone for all your help, much appreciated

I'll post back when I get another MB, hopefully for free

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by R. Proffitt Forum moderator / May 25, 2013 5:30 AM PDT
In reply to: returning motherboard

Sorry but any discussion of Mac OS X on other than an Apple computer is verboten. Why this is has been discussed at length but in short it's not something we can discuss in this forum as Apple's license for their OS does not provide for such use.

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