Bad CPU? i7-2600k Could use some help pinning down problem.

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jllaugh

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I just recently finished a new built, and am having a bit of a problem which I believe may be due to a bad cpu. When I push the power button, the fans will spin for a moment and immediately stop and you can hear the PSU 'click' as it begins and immediately stops sending power to the MB. I must pull power from the wall or reset cmos before the power button becomes responsive again. Everything will power on and run fine, but only if I've pulled powe from the CPU itself; as soon as I plug in the 12V CPU power the problem begins to repeat itself.

Upon finishing assembling the components and powering up for the first time, everything powered up then after about 3-5 seconds shut itself down, 3-5 seconds after that the machine restarted itself. This happened two or three times before restarting and continuing to run.

Once it stopped restarting itself and continued running, the monitor received signal, displaying the motherboard logo and bios screen which said "new CPU installed, press f1 to enter setup. I left it for the time being to wrap up some other things before finishing. I came back about 5-10 minutes later and as I was walking back to the machine it shut down again and has not been able to restart since.

I removed everything from the motherboard except only what was needed to run and the problem remained. I've reset the cmos, pulled the battery overnight, replaced the aftermarket cooler with the stock one. After resetting cmos or unplugging the power supply from the wall for a few minutes and plugging back in, the machine will try to restart but with the same results.

I'm guessing this is a bad CPU but I'm confused and concerned. Why would it seem to work at first and then stop? It appears that the CPU wasn't DOA which causes me to wonder what else could have caused the CPU to fail. That concerns me because if I get a replacement, what if some underlying problem causes that one to fail, too?

I really appreciate any feedback or suggestions anyone might have to share with me.

Asus P8-Z68 Pro V3
i7-2600k
OCZ 160gb Vertex 3 SSD
OCZ 850W
16gb DDR3 1600
 
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abekl

abekl

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Jul 8, 2011
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Unfortunately, in a case like this there are three likely culprits (MB, CPU, and PSU) and you have no choice but to work through them one by one until the root cause is found. Frustrating, I know, but rest assured that your effort isn't being wasted, anyone would have to go through the same steps.
 
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J

jllaugh

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True, I will be able to test the PSU if I go to my brother's house and pull the one from his machine but unfortunately I don't think I will be able to test the MB or CPU itself as I don't have access to another machine that will accept the socket type of the 2600.

I'll head to my brother's house soon though to at least rule out or identify the PSU as a source.

 
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D

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A bad CPU is possible but extremely uncommon.

Have you tried booting with a single stick of RAM?

Try "breadboxing" it. Take the motherboard out of the case and lay it on some cardboard or something nonconductive and see if it boots that way. It will rule out a motherboard to case short.

If it's not bad RAM then rule out the power supply. If it's not that I would RMA the motherboard before I would believe a bad CPU. Some bad ones get through all the checks but it is a fraction of a percent.

In all my years of building computers and knowing others who also do I don't know anyone who has ever got a bad CPU.
 
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J

jllaugh

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I've tried booting with a single stick of RAM, then subsequently tried with the other three sticks one at a time. I also tried breadboxing as anort suggested, with the same results.

After taking the board to my brother's house I was able to rule out the power supply, so no problems there.

At this point it is either the cpu or the board. I don't have access to another 1155 slot board at all so there's no way that I will be able to test the processor itself. Is there a way I can determine conclusively that it is the motherboard? Since everything will run when the 12V cpu power is unplugged would pulling the processor from the slot and then trying to power on work?

If I pull the chip but leave the 12V power plugged in and the motherboard powers up I guess that would rule out the cpu. If the problem is the same with the chip removed then I would know it is the mb. I'm asking because I don't know if attempting to power/run everything without the cpu installed is ok, or if anything will even work at all.
 
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harna

harna

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...looks to me like your system is under powered. If the CPU was DOA or died in the socket your mobo would be beeping at you.

Are there other 8/6 pin push connectors on the main-board you have overlooked to connect?

Are you using on-board video or a Video card that needs a power cable?

In either case the board will power up with logo and then shut itself down.

Take the board out of the case, remove all components and clear the BIOS. Check the board closely for connectors. Re-install it and connect the PSU to the board.

Add the RAM and CPU and use the on-board video if you have it. Test it now under minimal load before adding any other components.
 
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D

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Did you actually read any of the posts in this thread or just the title? :heink:
 
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J

jllaugh

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I just decided to buy another motherboard (unable to return/exchange the current one). If it works then I'll know the previous mb was bad, if it still doesn't work I'll know it's the cpu which I'll exchange and I'll give my brother the extra board.

I'll probably throw up an update Tuesday night when it arrives. Thanks for the feedback and suggestions.
 
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H

HEXiT

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Mar 13, 2011
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if you have an active pfc or similar over volting tech in your psu then the click you hear may be it activating and shutting off the psu.
the very first thing you do when you build a system and turn it on for the first time is go into bios and load optimized defaults. not doing so can cause potential problems...

possible solution...
reset the bios and clear the cmos. and try to boot the system. if you manage to post then get into bios and do as i said earlier.

simple test to see if the cpu is dead... turn off the pc completely at the wall/ turn on the monitor/ wait for no signal and time it to standby.
turn the monitor of and on again, but this time when you see no signal hit the pc power on. if the monitor immediately jumps into standby then the cpu is damaged/dead if it takes the normal time to go to standby the cpu is probbely (95% chance) ok.

i hope that helps... i know this test works on older pc's but i have never tried it on a sandy build so posting the results will help. even if it doesnt work as a test it means i wont have to keep writing this every time sum1 asks is my cpu dead and they have a sandy/neph part.
 
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J

jllaugh

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Thanks for the tip Hex; I went ahead and gave it a try. Unfortunately it looks like you may have to keep suggesting that to Sandy Bridge users a while longer, I didn't see any indication my CPU was bad (according to this test, it could still be) However, if I plug or unplug the monitor from the mb while everything is running and the monitor is already on, it will wake itself. After waking though, it will immediately follow with a no signal message. Don't think this is an indication of anything other than the monitor knowing it's been plugged in.

Update on the previous issue, though. I did get a new motherboard and I did not have the same problem, but something completely new. This time, with the replacement, after assembly, the board powers on, fans run, after 3 seconds powers off. Five seconds later the board powers back on but THIS time continues running however no post and no signal is received by the monitor. I called Asus and the only thing they had me try (Tried about everything else) was to plug just a 4-pin to the 12V CPU power header. After trying this, the computer did not restart itself after powering on but continued to run on initial power up.

After trying this, I still saw no signal to the monitor using onboard video. I tried once more with the video card plugged in and though just the 4-pin 12V was connected as before, the computer restarted itself again after 3 sec, then continued to run after 5 more.

At a total loss here. The Asus rep said I have a bad board and since I just received it to get a replacement through Newegg (Sending RMA tomorrow). I find it incredible though, that I would get two bad boards in a row. Would be convinced it was the CPU it the problem replicated itself between the two boards, but different problems with two boards? Could it be the CPU still or should I have just stayed away from Asus completely? I'm starting to think I'll go with the latter.

Side note: Not sure if this is an indication the CPU is fine, but the heatsink does get warm after it's been running a couple minutes so it seems like the CPU is doing *something*.

Going to see how next week goes with the next replacement mb and if I still have issues I'll RMA the CPU and possibly get a refund on the MB and stay far away from Asus in the future. I know they make good boards but this is insane.
 
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J

jllaugh

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Another interesting side note here that further indicates that despite all the has happened so far, the CPU itself still may be fine.

I've looked a little deeper into the problem with my second board and it appears that this is a problem that a few people seem to have, Maybe it is just the board.

There's a red CPU LED on the MB and it turns on and stays on after the MB has been powered on. Looked through the manual a couple times and didn't see a clear explanation for this.
 
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D

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Two bad boards in a row would be crazy high odds but it could happen. I got 2 bad hard drives in a row one time. That was fun to diagnose.

Asus boards are generally great and I highly recommend them. I have also been a Gigabyte fan for years and usually buy them for my own builds but have no problem using Asus for others. It goes back and forth between who is best. ASRock and MSI have also made great steps in quality here lately.

You tested with another power supply right? Here is a great checklist. Might as well try this just for the hell of it.

http://www.tomshardware.com/forum/261145-31-perform-steps-posting-post-boot-video-problems
 
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D

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From what I have seen people are calling that the "red CPU light of death" but without knowing your exact MB model I can't be sure.

For some reason the board is not initilizing the CPU. Could be a bad CPU.....or a short........or another bad board. Pull the CPU and look for any bent pins or burned looking places.

What kind of thermal paste are you using? Could some have spilled over the CPU on to the MB?
 
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J

jllaugh

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Hey there, my model is the Asus P8-Z68-V Pro Gen3.

Thanks for the link to the list. Wish I could say I hadn't been there before, lol.

I'll pull the CPU soon, but probably not until I'm ready to disassemble the board. I'm out of thermal paste I think. What's on there now is from a sample of CoolerMaster Thermalfusion 400 that came with an old CPU cooler from a previous build. I have a bottle of Arctic Silver around here somewhere but of course I can't find it now.

I'm positive that no thermal compound made its way onto the board. I was very careful when applying it and cleaned up the couple parts where a tiny amount hit the CPU bracket.

Since this is my second board, I inspected it very closely after I received it and before I installed any components. I detected no physical defects (though I suppose that's not to say I couldn't have overlooked one either).

I don't know about the CPU after installation on this board but upon close inspection after removing it from the last one I saw absolutely no burnt or otherwise out of the ordinary characteristics on the chip. The only difference to be seen was the dimples on the pins themselves from installation. I even checked to make sure every one had made contact while installed.

Thanks for helping me put some more thought into this. I also sent off a few PMs to folks who seemed to share the same issue asking them if they solved their problem and how they did so. (None of them updated their threads, unfortunately.) Hope I hear from at least one of them.

I'm going to tear my desk apart *again* and see if I can't find that Arctic Silver.
 
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H

HEXiT

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are you sure your psu has the rite requirements for the cpu if it doesnt then the symptoms your describing will show up... i know it sounds odd but some psu's will only work on amd setups while others prefer intel. something to do with the phasing i think... sum1 else will have to post on this as im not entirely sure... what make and model is your psu anyways?
 
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J

jllaugh

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My PSU is an 850W OCZ ZX. I am curious to see if that may be the problem, though I do remember reading positive reviews for that PSU from people using the same (or 2500k) CPU and MB that I chose. Could stil be an issue I suppose, but I did test with a different PSU with the same results.
 
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S

sharkpack

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Jllaugh, I'll be interested to hear what your final solution is. This is my first build and I relied on Tom's for a starting point when choosing the various components. I verified those parts with a local gaming machine enthusiast and changed out the memory to GSkill when the original memory I had chosen wasn't on Asus' approved vendor list.

I have the Deluxe version of the Asus P8-Z68. I am having the same issues you are having with the case being powered when the CPU isn't connected, along with the red CPU light. When the CPU power cable is connected to the mobo, I get the same click out of the PSU when I hit the power button. I've reseated the memory and checked all the connections.

I haven't started returning parts yet, as I'm hoping there is something I missed.

 
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S

sharkpack

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Ok - good news. I had a couple of connections wrong.

1. It's actually possible on this mobo to plug in the CPU power upside down if you're not careful. For whatever reason, this one can. Make sure there is a "click" when you finish plugging the CPU power cable into the mobo.

2. Make sure the memory is seated all the way in. On this mobo, there is only one latch, so it's actually possible to have one side of the card latched and the other unseated.

I no longer get the "click" when I turn the computer on with no results, I'm booted and rolling.
 
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L

leon2006

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You should try a different PSU. I have similar motherboard that you are using w/ 2600K. No issues at all. I built a new pc last December same motherboard and CPU and everything is GOOD.

The most reliable component on the PC is the CPU. The probability of having 2 bad MB is low.

Try a new PSU. I have a PSU that have similar symptom as you (different brand).

I kept one of my Antec 850W PSU that failed. I had 3 of these Antec 805W that failed. This PSU has no physical sign of any defect(no burn, no smoke, everything is clean). Except that the PC won't both when connected. All the hardwares and fans crank up but the pc won't boot. When i plug in my new PSU everything works.

Try a new PSU...

 
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