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Mobo Or Power Supply?

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#1 gibsteroon


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Posted 21 July 2007 - 02:50 AM

I just built a new system today from parts ordered off Newegg. For reference, the relevant components are:
Athenatech A449SL.400 Silver / Blue Steel ATX Mid Tower Computer Case 400W Power Supply - Retail
EVGA 122-CK-NF66-T1 LGA 775 NVIDIA nForce 650i Ultra ATX Intel Motherboard - Retail
Intel Core 2 Duo E6420 Conroe 2.13GHz LGA 775 Processor Model BX80557E6420 - Retail
MSI NX8600GTS-T2D256E-OC GeForce 8600GTS 256MB GDDR3 PCI Express x16 Over Clock Edition HDCP Video Card - Retail
SUPER TALENT 2GB (2 x 1GB) 240-Pin DDR2 SDRAM DDR2 800 (PC2 6400) Dual Channel Kit Desktop Memory Model T8UX2GC5 - Retail

So, anyhow, I got everything put together and tried to fire it up. Turning on the power supply caused the CPU and GPU fans to rotate for a split second, but nothing else. The case's power button was not responsive. Eventually, after much fiddling, I turned on the power supply while holding the power switch down and it powered up. However, I smelled smoke and quickly shut it off at the power supply. A small chip on the motherboard had been smoking.

I soon realized the problem was that I neglected to put the spacers in between the motherboard and the case (thus shorting the motherboard with the metal case interior). Just for kicks, I took everything out and installed the spacers, and then replaced the motherboard and other components. It now booted. But then quickly shut down after 5 or 10 seconds. I booted it again. Another quick shutdown. I kept trying and it seemed that the computer would stay powered for longer and longer each time. Eventually it stayed on long enough to see the boot screen and get into the BIOS config. I once even got it to enter the Windows installation before it powered off without warning. It seems worth mentioning that during these times I got past the BIOS screen, the IDE drive detection took an extremely long time (30-45 seconds).

After this long story, my question is what I should do. It seems obvious that the problem is either with the cheap power supply that came with the case, the motherboard that I apparently fried, or both. From what I've explained, which do you think it is? Unfortunately I do not have extra hardware lying around to test any of the components individually. Should I even have any hope left that my motherboard is usable?

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#2 dc3


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Posted 21 July 2007 - 06:00 AM

Hi gibsteroon and welcome to bleeping computer.

Did you use thermal compound when you installed the heat sink to the PCU, or did it come with a thermal pad?

Did you connect the square four pin PSU connector to the motherboard for the PCU?

One of the things that seems to be a given with most cases sold with a PSU, and that is that the PSUs are generally cheap, that could be a problem. If you have a voltmeter you could check out the voltage of the different rails. With the computer unplugged remove the 24 pin connector on the motherboard and place a wire jumper from the green wire socket to any black socket, this bypasses the motherboard's start up. You can now plug the computer back in and measure the voltage. You can find the color code and associated voltages at this site.

Edited by dc3, 21 July 2007 - 06:03 AM.

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#3 Sneakycyber


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Posted 21 July 2007 - 01:33 PM

If the motherboard started smoking and you havent RMA'd it you fried a capacitor and its not likely to work properly. Replace the board with a new one and folow dc3's reccomendations on the proper heat sink installation. If you have replaced it and your still having problems please list the Voltage specifications on your power supply and how many drives you have.

Chad Mockensturm 

Systems and Network Engineer

Certified CompTia Network +, A +

#4 gibsteroon

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Posted 21 July 2007 - 01:50 PM

Hi dc3 - thanks for the reply and welcome!

The heatsink came with pre-applied thermal compound that I accidentally smeared a little with a gloved finger during installation. It still covered roughly the same surface area, so I didn't think it would be a problem, at least immediately.

Yes, the four pin PSU plug is connected to the motherboard. I may be able to find a voltmeter to borrow from someone to check the PSU rails. It turns out I might also be able to borrow a spare PSU from my department's computer lab as they recently replaced most of their machines. Still, do you think it likely that my motherboard is okay after the smoking incident? I've never dealt with a shorted/smoking motherboard, but I imagined such a thing would be completely dead and unable to boot.

#5 garmanma


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Posted 21 July 2007 - 03:47 PM

If static can kill a CPU I'm sure a direct short or smoke is not a good indication. Why even gamble on it
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