New computer (just built) -- shuts down by itself

[kic]

Hi folks. This is by no means my first computer I've built, but this is the first time I've run into this problem, and unfortunately, I don't have all of the extra components I'd like to have to try swapping things.

The short version is: I just put together a Core 2 Duo E6400 based system on an ASUS P5B-E, with 2 gigs of Corsair XMS 6400C4 (paired 1 gig sticks) RAM, an OCZ 650w GameXstream PSU, and a Radeon X1950 Pro.

I originally assembled this with a Gigabyte GA-965P-DS3, but I ran into problems where I could get the system to POST, but after a few seconds (maybe 15 top), it'd shut down. After it would do that, subsequent attempts to boot would result in an even faster shutdown, usually so fast that I couldn't get into the BIOS, or it'd die right away once I got in.

Knowing that the Gigabyte board is picky with memory, I tried some generic 533mhz RAM and that changed nothing.

Thinking that it was the motherboard, I ordered the aforementioned Asus board. I've now assembled that, and it's sitting all together with Windows installed (yeah!), but it's still dying.

So after clearing CMOS I was able to get back into Windows, install updates and drivers, and now it just died on me while installing a game. No warning, just died. Poof.

I just opened the case up and everything is cool-luke-warm at worst. The heatsink fan (Intel OEM) feels secure. I've looked and confirmed that every fan in the system is spinning while the computer is on.

I don't have another PCI-E video card to test with; I don't have another power supply to test with; when I tried with generic 533 mhz RAM on the other motherboard, I had exactly the same result.

I call upon the wisdom of those wiser than me and ask, please, what's the most likely culprit here? I'm leaning toward the power supply, but I honestly don't know (and am getting tired of buying extra parts while trying to troubleshoot this thing, but don't see much recourse otherwise).

Please, a little help would be greatly appreciated. Thank you.

 

[Gambit808]

Hi Kic, sounds like a video card or PSU issue! make sure yuo have enough amps on your 12 volt rails for the PSU. have you took everything out and try to bench test the system with only mobo, one stick of ram and vid card only out of the case? your problem sounds just like what i was haveing when i first got my ATI 9800 pro. it turned out to be the PSU! well, thats my 2 cents but i hope it helps.

 

[Gambit808]

Hi Kic, sounds like a video card or PSU issue! make sure yuo have enough amps on your 12 volt rails for the PSU. have you took everything out and try to bench test the system with only mobo, one stick of ram and vid card only out of the case? your problem sounds just like what i was haveing when i first got my ATI 9800 pro. it turned out to be the PSU! well, thats my 2 cents but i hope it helps.

 

[Gambit808]

crap
sorry about the double post : (

 

[kic]

Well, everything is in the case right now, but I just finally managed to get the Asus Probe software installed and it said the CPU was running at 88c! Yikes!

I guess that hsf isn't on as well as I thought it was (or else the paste is on too thick). Or else something is wrong with either the CPU or hsf. Ugh. I really don't want to take it off, clean it, and then reapply the paste. Such a hassle. I'm hoping this solves the problem (and it'd certainly explain why it's turning off -- self-preservation).

 

[mechBgon]

edit: sounds like you found a heat issue while I was busy typing up a post.

I was looking at pics of both the Gigabyte and Asus. Here's a quick potential issue you can check: remove the motherboard from the chassis and make sure there isn't a standoff in the location circled in this pic.

Some motherboards do have a hole there, some don't, and your Asus (and Gigabyte) are in the don't-have category. But your case would have a standoff position there, so make sure it's vacant, or else it could be shorting out stuff on the underside of the motherboard. Thermal expansion/contraction could conceivably make it short out at random. Just an idea, anyway.

You might also get Asus Probe II (in Utilities) and watch your CPU temperatures. Are they staying reasonable? If not, maybe something's keeping the heatsink from pulling heat off the CPU properly, such as a defective mounting fitting.

Other than that, I doubt you need reminding, but you did get your video card's 6-pin PCI-Express power cable plugged in? Checked that everything's snugly seated (RAM, power cables, cards)?

 

[Gambit808]

yea.. wow.... 88c! <----bad! well, i bet you thats the problem! just take it off, clean it real good and reapply some thermal paste and reattach the HS/F and you should be on your way!!!!

good luck

 

[QuEeNyGuRl]

I just had the same thing happen to my work computer. My temporary solution is just keep the case open for now. It hasn't shut off by itself with the case open.

 

[kic]

Well, I've removed, cleaned (glad I got that high-purity isopropyl alcohol the other day), and reapplied the paste, going by what the AS folks have to say (I actually have OCZ Ultra 5+ but I've seen people say it's either close to AS5, or it actually is AS5, just in a different package).

I'm sitting here staring at the temp now (I'm posting from my notebook) and the CPU is hovering on 38c idle. Not too bad, and I don't think idle temps (assuming this stays) will vary much once the panel is back on (gotta love the 25cm side fan).

I'll thrash the CPUs in a minute or two and see how high it jumps, but I'm feeling better about this now.

The thing is, I'm wondering if heat has been the problem all along. I really had reason to think it was the RAM while using the Gigabyte board, but I'm thinking that maybe it was heat now, especially since the symptoms are (were?) the same.

So, perhaps the real question is, assuming this thing keeps running without problem, do I build another machine with my extra board?

Anyhow, I appreciate everyone's input on this and I hope I can update this tomorrow with good news of the machine still running and no components fried.

Edit: just to add, I actually thought of heat this time around, but when I couldn't find a panel in BIOS for it, and everything seemed to be okay in Windows, I totally forgot to check until it crashed again later. Whoops! But I never even considered heat when on the first motherboard, but I'm betting that was the problem. Sometimes I need that reminder to look at the obvious things first.