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Old March 25th, 2013, 02:31 PM
Digerati Digerati is offline
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Join Date: Jan 2007
Location: Nebraska, USA
Posts: 2,465
I agree that you should ensure you have good power first, but unfortunately, the paper clip method is not conclusive. A bad PSU can still "turn on" but that does not mean all the voltages are present, within specified voltage tolerances, or providing "clean" (marginal ripple) DC voltage. Plus, and this is very important, to properly test any power supply (PC PSU, a battery, or even a car engine) the power supply MUST be tested under a variety of "realistic" loads. This cannot be done with the main power connector removed from the motherboard - and sticking hard, sharp, highly conducted meter probes into the heart of a running computer should be left to someone with more experience and good insurance - and steady hands.

The only way a PSU can be conclusively tested is with specialized power supply "analyzers" or an oscilloscope with the PSU under a proper load. Both require a skilled and trained technician for proper use of the test equipment and understanding of the results.

For the vast majority of home users, swapping in a known good PSU is the best way to test your PSU. Alternatively, most repair shops will test your PSU for free, or nominal charge. Or you can use a PSU Tester. However, these testers do NOT test for excessive ripple and other anomalies that affect computer stability (neither do most multimeters), and these testers only provide a small "dummy load", not a variety of "realistic" loads. So while not a certain test, these testers are better than nothing. They are also great when using a spare PSU for testing fans and drive motors as they signal the PSU to turn on when plugged in.

Since that is an older eMachines computer, I would inspect the motherboard for bulging or leaking electrolytic capacitors. This was a problem several years ago - especially with budget computers. Failed or failing electrolytic capacitors are a common cause of sudden, but seemingly random system lock ups and reboots. The capacitors look like tall soda cans, many of which surround the CPU socket.

Failing (including flawed and/or abused/over-heated) capacitors literally bulge at the seams due to excessive internal pressures. Extreme (and very rare) cases result in a firecracker type explosion or “pop” or “snap” type sound that can really stink up a room. Typically, electrolyte just oozes from the pressure relief point, which appears as a symbol or letter stamped in the top of the capacitor casing. The electrolyte can be caustic to motherboards and flesh. Look for white to dark-brown, dried liquid or foam on the tops or bottoms of the capacitors. Bulging capacitors are a sign leakage is about to occur.

A motherboard with bulging or leaky capacitors can be repaired, but often it is more cost effective in the long run to replace the motherboard.

Be sure to first power down, unplug the computer, and keep yourself discharged and at the same potential as your computer by touching the bare metal of the case before reaching in.

I don't think it's a heat issue either, because it does quit within less than a minute of start-up. After I start it a few times it seems to stabilize and stay running.
Well, a CPU with a failed fan can overheat in just a couple short seconds, so heat cannot be ruled out completely. I would verify that all fans do indeed spin up to full (or near full) speed when first powered on.

Old fans are like me - stiff and slow to get moving first thing in the morning.

The fact the computer does run good once it stabilizes "suggests" the PSU is good.

You might try running with just one stick of RAM at a time and see what happens.
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