I'm in the process of building this, right now it has these installed, powered, and seemingly working:
Here's the issue. The comp boots up fine, we get to some Guru screen complaining about the CMOS, it's not set up yet so I don't think thats the issue. From there, I can go into the BIOS and look around. All RAM is detected, processor is detected, and everything displays properly with the video card. Sounds good, right? Nope!
Randomly, the PC will just turn off. It's usually about 1 or 2 minutes after pressing the power button, but it can be instant sometimes. Nothing specifically triggers it, it just happens randomly. I tried another power supply, and a lower-power videocard... same problem.
Any ideas? I'm at wit's end here. All help is appreciated!
Matt, perhaps your processor is overheating...did you try reapplying goop & reseating the heatsink?
If not, try reseating the video card, cables, memory, etc. You can also try running the system with one stick of memory at a time. Make sure you don't have a loose screw or something else that may be shorting out the motherboard. I recommend covering any unused molex connections with scotch tape (or those nice plastic black covers that came w/ Dell PC's, if you can get 'em).
Doesn't take long at all for a CPU to heat up. Even when your in windows, and looking at the core temps, using TAT or Prime95 to stress the CPU, it cools down immediately according to the readings when you stop the program. So I'm talking 60c down to 44c-42c, even vice versa when you start the stress test.
You can kind of compare it to a 65watt light bulb. After all it is a silicon base core with just electricity running through it.
Also another reason you should never start your PC without the HS installed, from what I've read in the past of people who thought it took awhile for CPU's to heat up.
Go to the health monitor of your bios and let it run for about 5 mins or so to see how warm your CPU gets, and let us know.
Ooopphh... from the sound of that, if your system doesn't stay on long enough for you to look at the settings, I'd re-seat the Heat Sink. Cleaning off the bottom of the heat sink, and top of the CPU with rubbing alcohol, and putting fresh thermal grease back on by it's instructions. If your using the stock heat sink, make sure the 4 pins are through the MB:
And here's a video to watch, if you never did a 775 socket setup before on the CPU:
Oops. I got a little lazy. I am posting from Saudi Arabia on a sometimes erratic 'net connection and when it is acting up, I sometimes do not follow links. Apologies.
If after doing the obvious things like reinstalling the HSF and checking all the connections, you may have to resort to serious troubleshooting. I saved a long reply to someone else with a "new build" problem. Your problem is a little different. The computer is not completely dead. It almost works. This is a more difficult problem. Yours comes up, then immediately or after a few minutes, it shuts down. So you will need to wait a few minutes between steps. Parenthetical commwents in italics are not part of the original post. ___________________________________________________________________________________
I see quite a few "new build failure" threads here. The following is one of my replies that I have cleaned up, expanded, and saved. This assumes that the new build is completely dead. Even if not, the same principles still apply.
Assuming the speaker is properly connected to the motherboard, no beep means the POST did not run. A bad video card or bad memory would still generate a beep pattern indicating video or memory problems.
(You should become familiar with the POST codes. Your motherboard manual may list them. If not, google something like "<motherboard brand> or <BIOS brand> post codes".)
Turn off the computer with the switch on the back of the PSU or unplug it. Wait a few minutes. While you are waiting, double check all the cable connections. Make sure that the case switches and LED's are connected correctly. Pay close attention to the main power connector to the motherboard. If the computer is completely dead, the case power switch may be bad. Swap it with the reset switch. Turn on the computer. If it still doesn't work, you have to resort to serious troubleshooting.
If so, six possibilities:
1. The motherboard is improperly installed in the case, shorting something out. This happens surprisingly often.
2. Bad or inadequate PSU. A working PSU will send a control signal call "PSGood" to the motherboard. The motherboard needs this signal before the CPU can start the boot process. A problem with any output should kill the PSGood signal. Losing the PSGood signal forces a CPU reset. PC's with modern components NEED a good PSU. The forums here contain guides on how to select (by brand and capacity) a good PSU. And even a reputable PSU may be DOA or have other internal problems. (Since you tested the PSU by substitution, it is probably not the problem.)
3. A bad drive or video card affecting the PSU. (Video card likewise.)
4. Bad memory.
5. Bad CPU.
6. Bad motherboard.
CAUTION - you need to remove power (ON-OFF switch on back of PSU or unplug it) from the computer each time you install or remove anything. I know this sounds stupid, but you'd be surprised ...
Disassemble everything. Breadboard (assemble the components outside the case on an insulated surface) only the PSU, motherboard and speaker, and CPU and HSF. If the problem was in the CPU socketing, reinstalling the CPU should solve it. Now you need a way to turn on the computer. I use wiring, switches, and LED's scavenged from an old case. (Since you can sometimes enter the BIOS, CPU socketing probably is not the problem.)
Turn on the computer. If the fans start spinning, you have a good 12 volt output. Look for any motherboard LED's. If you hear beeps, the computer at least started POSTing and the PSU, motherboard, and CPU are probably good. No beeps means that at least one of the three are bad. At that point, all you can do is test the parts by substitution. I say "probably good" here because an inadequate PSU could pass this test and fail later when it's more heavily loaded.
If you heard beeps, that should indicate that the POST detected memory or video problems (no surprise, there's no memory or video card installed). Install the video card and plug in the monitor. Turn on the computer. No beeps now means that the video card is shorting out the PSU. Otherwise, at this point you should see something on the monitor if the video card is good.
Beeps now should indicate memory problems. Install the memory. No beeps probably means that you have a shorted memory chip. Dual channel motherboards can operate with only a single memory module installed. Install each one separately and test. Sometimes motherboards do not properly set the memory operating voltage. That is a more complex problem than the simple "It won't start" problem. ("Simple" is not the same as "easy".)
Now, you should see a "missing keyboard" error. Turn off the PSU and plug in a keyboard.
Turn on computer. Try to enter the BIOS to set date and time and verify the amount of memory present. If you can do this, it means that all the expensive parts are probably good. (You can do this - sometimes. Nasty.)
Start plugging in the rest of the components and test. No beep, and you have found the problem.
If everything works, it probably means that something was improperly installed in the case. Reassemble in the case and test. If you are lucky, everything works.
I always breadboard a new build. I pretty much reserve the fourth port of my KVM switch for system testing.