Asus p8z68 infinite loop

[Sheekster]

I have a asus p8z68 motherboard with i5 2500 k CPU. It has been working solid for around 5 months.

This morning I come find it in a power loop.

 

I have read forums and took advice such as

-reset CMOS

-reseated CPU and applied new thermal paste

- removed graphics card, all USB apart from keyboard, hard drive and optical drive.

- reseated tax cables

 

I find that if I unplug the main cable from my psu it will boot and pass post, after roughly a minute it will reset then go into an infinite loop?

 

Is this a broken psu.

 

Cheers for the help guys

[KenB]

Hi and welcome to ExTS

 

I would be inclined to strip all cards etc off the m/board and leave only the 20(4) way connection from the PSU.

switch on.

You should get POST beeps and it should be stable.

 

see here

http://kenspchelp.co.uk/viewtopic.php?f=36&t=246

[Sheekster]

Thanks for the welcome.

 

All cards are stripped and hdd

My confusion lies in the fact that if I remove power completely and reapply, the POST works and boots to bios( this is because hdd is removed) after a few minutes it will restart all by itself, it will then just be continually power looping

 

Confused

[KenB]

It could be CPU overheating.

 

If the machine has been off for a while does it take longer before it restarts when initially switched on ?

Then - because the CPU is hot - it restarts almost immediately ?

 

Does the CPU fan rotate quickly ?

[Sheekster]

I am going to get a multimeter from work and do the test suggested on the link you posted

 

Cheers

[Sheekster]

When it does manage to boot the CPU temp is around 39 I live in Cyprus and the room temp is around 30

[KenB]

Those temps look OK

 

Test the PSU and let me know what you get.

Remember - the voltages need to be within about 5% so a reading of 11v on a 12v connection is low.

It is 8.3% out.

 

If the 5v supply is reading 4.5v this is actually 10% out.

[Sheekster]

Ok will do

 

Cheers

[Sheekster]

8 pin tax was 12.37 v

Molex red 5.13

Moles yellow 12.19

[KenB]

Those voltages are obviously OK.

 

The only thing with that test is that there is no load on the PSU.

 

If you can swap the PSU ( wattage will not matter too much ) this will confirm if yours is OK.

 

The problem lies with either the PSU or the motherboard.

 

You could phone a local tech and ask how much he would charge to test both.

 

Just a thought ........there isn't a build-up of dust is there ?

[Sheekster]

I've taken my motherboard out of my case and took it round a friends. We put 24 pin power and 8 pin power keyboard and ram. It POST first time and stayed on for 10 minutes. After that we removed power as that was proof enough for us

 

I have come home left motherboard out of case and put same cables in. Test failed. Post the first time stayed on for a minute now in a continuous loop.

 

That has to prove it's my PSU even though the measured voltages were good?

 

Which I am so happy with as it the cheapest thing to replace!

 

Dust in the psu? I havnt checked!

Edited July 4, 2012 by Sheekster

[Sheekster]

No real level of dust. My case has a psu inlet with filter mesh which is quite good

[KenB]

That has to prove it's my PSU even though the measured voltages were good?

 

Which I am so happy with as it the cheapest thing to replace!

 

Looks like you need a new PSU which, as you say, is by far the cheaper option :)

 

[i did say that the voltage test was not under any load :) ]

[Sheekster]

Thanks for the help Ken, it was much appreciated.

[KenB]

You are welcome - let us know how you get on :)