[SOLVED] Is my cpu or PSU stuffed?

bensonae

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Recently, my computer stopped posting (black screen during post), there was no power led, the system had to be turned off by holding down the power button (simply pushing it didn't work), and every time the thing powered off, the motherboard led would blink for a bit then stop (no recognisable pattern). I have checked that this is not a memory issue, as all i had connected was PSU, motherboard and CPU. I have had the motherboard professionally tested, and it is apparently not the issue, and I thought I had eliminated the PSU as being the issue (all fans were spinning in case, and on CPU cooler), so does this mean that the CPU is kaput?
 

bensonae

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Turns out that the MSi board was faulty, as said by the distributor. So i got a full refund of purchase price, and I have a working Gigabyte Z97-UD3H-X board in my computer.

All points aside, thanks to everyone who has tried to help me solve this issue, it certainly hasn't been fun, but it's nice to know that people out there actually give a s***.
 

Darkbreeze

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Just because the fans were spinning doesn't mean the PSU is out of the woods. You can get power to the board, and therefore the fans, through the four pin molex or the motherboard headers, and still not have power to the cpu through it's four or eight pin connector. It could also be the CPU, or something else entirely.

HOW have you checked that it's not a memory issue and what do you mean by "had the motherboard professionally tested"? Did you take it to a shop where they bench tested it with their own RAM and CPU? Why would you have not had them also swap your CPU in at the same time to see if it still POSTED if you went through that much trouble? How did you test the RAM if the system doesn't post?
 

bensonae

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To be clear, I'm running an Intel build, with i5-4690k, cougar rs 750w, msi z97 guard pro, g.skill ripjaws 8gb ram. And by professionally tested, i mean i had it returned to reseller, where they took the motherboard and put in into their test system, and apparently it worked perfectly. And i couldn't give them my cpu, because i got the mobo with an online reseller.

And i tested the ram by performing a systematic deconstruction of my system, starting with my drives, and finishing with only cpu, mobo and power supply connected. This would have given me an error code different to the one i was getting if it was the ram, i looked this up online beforehand. I also looked online to find a flashing pattern (of the motherboard led) for cpu failure, but like i said previously, the patterned did not change during the deconstruction, which would have indicated where the faulty part was. It also did not present with a cpu error pattern, which would have triggered immediately if it had been the cpu. And yes, i did check for the specific model of motherboard, as it tells you these things in the manual.

Also, if it was an error in getting power to the cpu, and if at the same time the motherboard was functioning as it should, then it would give the associated error pattern as if there was a hardware failure inside the cpu itself.
 

shortstuff_mt

Illustrious
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The reviews I've found for Cougar PSUs are not good. This sounds like the PSU has failed/is failing. What GPU do you have? I see the rest of the components listed, but no mention of GPU. Fans running do not mean the PSU is providing enough power to run the machine.
 

Darkbreeze

Titan
Moderator
Yeah, that's what I said but he apparently believes the motherboard will notify him of that the same as with an internal CPU error. Which is likely not the case in some circumstances when the board isn't getting power to the cpu circuit. I think this would be dependent on the board design. Not every board is guaranteed to act in an identical manner in every circumstance.
 

shortstuff_mt

Illustrious
Moderator
CPUs VERY rarely go bad. I would exhaust ALL other options before even considering the CPU being bad. I've built a lot of computers over the years and I've dealt with a variety of faulty components, but I've never seen a CPU that has failed. That includes some of my personal computers that have had significant overclocks and run 24/7 for years.
 

Darkbreeze

Titan
Moderator
I built a lot of them as well, and I've seen CPU failures but it was almost always due to a problem with the power supply or motherboard causing the cpu failure from something voltage related. Or, user error as in forcing them into slots wrong and bending pins. I've also seen them fail when exposed to improper conditions like the guy who tried to run the unit in his garage because he was overclocking and thought the cooler ambient would be beneficial.

Unfortunately the ambient was about 5F and after sitting in the unheated garage for two days, it had built up frost inside the unit since his side panel was off. That was bad enough, with a rapid cold to hot start but the frost of course almost instantly turned to water and toasted the chip by leaking into the socket and shorting it out. Anyhow, there are possibilities for CPU failure, but it isn't common unless something else causes it or you cause it yourself.
 

bensonae

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Sorry, I was kinda stressed out when posting this. Yes, during the deconstruction the gpu was removed too (Gigabyte R9 290x windforce), and it made no difference.

So essentially, my PSU is kaput in some specific sense, and I'm going to need to return that to reseller in order to see if that is the problem?

NB: Still not sure how a PSU can blow a very specific set of lines without doing the whole unit, but I'll go on faith for now.
 

Darkbreeze

Titan
Moderator
Because there are separate lines of supply on a PSU. Generally, one, two or three +12v rails, 3.3V circuit, 5v circuit, etc. You could easily toast any individual circuit and still have measurable power in other areas.

The thing to do would be to test the unit or replace it with a known good unit to see if the problem still exists. If you can borrow a PSU for testing, great, or if you have access to a multimeter, you can test it like this:

https://www.youtube.com/watch?v=ac7YMUcMjbw
 

bensonae

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Yeah, fair enough i suppose. I figure I'm probably going to end up replacing the unit anyway (note to all out there, never skimp coin on your mobo or PSU).

Which of these three would be recommended?

Silverstone Strider Gold 750W ST75F-GS
Corsair CS750M Modular 80 Plus Gold Power Supply
Antec True Power Classic 750W 80 Plus Gold Power Supply
 

Darkbreeze

Titan
Moderator
Again, not saying it IS the PSU, just that it might be. You could be one of those half percent that has a CPU issue but with your symptoms, especially with no LED's and no indication of power, it sure seems targeted to the PSU. Maybe pull the 4 or 8 pin CPU plug and check for any abnormal coloring on the socket and plug. Same for the 24 pin.
 

bensonae

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I don't know what "abnormal" would be in this case, but to confirm that there is no blackening around any of the connectors on either 20+4 or 8 pin leads.
 

bensonae

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Well, reseller told me that nothing was wrong with my board, so my guess is that in fact a very small but delicate part of my PSU which is somehow the most important component in there (note sarcasm) has decided that life is not worth living, and as such has committed dishonourable suicide. Little bastard. :(

NB: I don't actually have the board back, they are still processing the warranty claim, and won't get back to me until Monday. Then it will probably take another week to get my board back from them, after I pay for shipping (for the 4th time).
 

bensonae

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Have ordered a new PSU, EVGA supernova 750W, and i'm getting another motherboard so that I can test if my old PSU is still crapped up. Also, the new motherboard is a Gigabyte z87x-UD3H, which is far better than the MSi i was using.
 

bensonae

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Well, it would seem that the cougar psu wasn't actually stuffed. I connected it to my old AMD based build (X2 Athlon, gigabyte micro-atx board, Gigabyte ATI HD 4350) and the thing booted for the first time in 2 years. Was able to easily overclock the old athon X2, card was fine (doesn't draw more than motherboard power, so all good there), absolutely no issues. So my guess is that somehow there is a minor flaw in the MSi board that doesn't rear its head until one tries to overclock, which is why the retailer said that everything was fine. Well, I now have 2 working systems, so I might use the old one as an HTPC, god knows it is beyond useless for gaming now. :)
 

Darkbreeze

Titan
Moderator
To start with, that's a Tier 3 board, overclockable, but not really great for overclocking. Clearly the board could be part of the issue.

http://www.tomshardware.com/forum/id-2383187/motherboard-tier-list-z97-chipset.html

Secondly, not once did you mention anything about overclocking in any of your posts above, which might have been helpful since overclocking creates a whole new category of potential issues, and potential remedies as well.

Glad to hear all of your hardware is ok though. Chances are good that the older system, either has a board with better overclocking stability, or presents less demand on the PSU since all it's components likely have a much lower TDP. The Athlon X2 is a 65w TDP chip. The 4690k is an 88w TDP chip. That might not seem like much but it might be enough that when it's four cores are overclocked, which significantly increases the current draw per core, to push a PSU that's not of sufficient quality that it should be used with gaming cards and overclocked systems in the first place, over the edge into unstable territory.
 

bensonae

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Dec 12, 2014
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Turns out that the MSi board was faulty, as said by the distributor. So i got a full refund of purchase price, and I have a working Gigabyte Z97-UD3H-X board in my computer.

All points aside, thanks to everyone who has tried to help me solve this issue, it certainly hasn't been fun, but it's nice to know that people out there actually give a s***.
 

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