Boot on/off loop problem GA Z77 D3H

[slowlearner]

Hi

I am in the process of building my first computer. I bought a Gigabyte GA Z77 D3H rev. 1.0 motherboard and an Intel Core i5 2500K CPU, which Gigabyte confirm is compatible in their specs. I have connected it to an Antec TP 750w PSU and have two sticks of Kingston KVR1333D3N94G 4GB memory.

When testing the above I cannot POST. I get an on/off boot loop. The CPU fan starts, runs for about four seconds, switches off for two or three seconds and then repeats. I've tried the PSU on another machine and it's fine.  I've also checked it using a PSU tester and all the lights come on. I've had the motherboard replaced, with the same result. I've tried the memory as single sticks with the same result. I've removed the heatsink to see if it is properly seated and can find no problem. The thermal paste had spread in a thin perfect circle, so overheating would not seem to be an issue, even though it is the generic heatsink.

Where to now? Any suggestions will be grabbed with grateful hands. Please remember that anything too technical will just sound like magic to me, so keep it simple, please.

[absic]

Hi there,

Apart from the CPU, PSU and RAM, what other parts are you using?

Have you tried putting together the basic parts, CPU, one stick of RAM, monitor, keyboard outside of the PC case to eliminate the possibility of an electrical short?

Have you connected all the necessary power leads to the motherboard (and GPU if you are using one) and are the inserted properly?

If you are using a GPU rather than the onboard graphics remove this and see if the system will start.

Have you tried clearing CMOS to see if that helps?
To do this, you will need to disconnect the motherboard from the mains power supply and remove the motherboard battery for a few minutes (I usually make a cup of tea here). Short the CMOS pins on the motherboard or, if it is connected to the power switch on the PC case press this to clear any residual power in the capacitors. reinstall the motherboard battery and try to start the PC. If it does start up you will have to set the Date and Time in BIOS.

[Legalese]

Well... Here is something you might want to check out.

My computer was built a year ago, board of choice was the X79 UD5. Everything was great until about a month or so ago, when the computer went into (lo and behold, this may sound familiar) a continuous loop of restarts. The fan would start going, then stop. Rinse and repeat. After pretty much ruling out everything else, the only remaining options were the board or the cpu.
CPU was fine.
Board was exchanged under warranty to a factory re-cleared similar board. Checked on site, worked fine. After being installed in the computer, you guessed it, the restart loop started again.

Out of sheer frustration, my techie (who also has an electronics degree) started pushing on different areas on the ("new") board to see if it was a connection issue.
Turned out that there is a little coil on the board that supplies power to the cpu. When pushed a bit, start up was fine. When the tiny pressure was released, reboots returned. At this point the electronics expetise came to play.
Problem was narrowed down to a problem with the soldiering of the "legs" on the other side. The suspicious area was cleared, and inspection found that the area that was supposed to be soldiered (and thus "green free"), was "green".
Said area was cleaned. Resoldiered manually (there was really no point to take the board back to be exchanged again after board 2 suffered from the same issue).
The computer is now working perfectly.

From the desctiption of your problem, I'm willing to bet that you have the same problem, and suggest you ask the local warranty representative to try and check along the lines described here. If your computer will indeed boot up with a small amount of pressure applied on the right spot to take care of the connection problem, you will know for sure.

And a tiny suggestion for the powers that be, please check the production line and make sure the soldiering process is configured properly. I googled the problem I had, and discovered I was not alone with those symptoms.
I guess I'm just lucky to have a pro building my computers for me.

If this reboot problem is happening all over, then you guys may really want to check and see if there is a repeating problem in the manufacturing process. Everything looked great upon visual inspection. Had to use a soldiering iron to expose the area to see that the factory soldiering process simply "missed" its mark, and a "manual fix" had to be applied by someone who really knew their stuff.

At least the computer is finally back now. I just hope the same problem does not repeat itself with a different "loose connection" at a later date.

[slowlearner]

Hi absic

Apologies for the delay in replying. It's the bare motherboard, CPU and heatsink, one memory stick and PSU that I have set up, with the monitor connected. I have cleared CMOS and I haven't used the GPU, as the motherboard has a VGA out. I've connected th 24 pin and 4 pin ATX cables.

Since reading your post I've removed the battery and shorted the CMOS, but still the same result. Could it be a BIOS issue?

Legalese, I've tried pressing the motherboard in various places, but no luck. Mind you, it was rather a random process.

[P . P . L .]

Slowlearner,

I might have missed it but is the CPU new or used  & have you tried it on another M/B,  is the chip good?

[slowlearner]

Hi

CPU bought as new. I don't have another motherboard to try it on.

[slowlearner]

Hi

Taken in my local computer shop today to see if they can determine what isn't working as it should.

[ysw]

do u test it without chassis?
or you may try different PSU to check.

[slowlearner]

Hi

Problem solved. The CPU is dead. On the bright side, all the other parts seem to be working well. Pity it's the most expensive item that let me down.