Overheated Pentium 4

Posted 02/05/2010 at 10:00am | by The Maximum PC Staff

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My 5-year-old computer—Windows XP, 2.4GHz Pentium 4, Antec server case, 430-watt PSU, Seagate HD, and two 256MB Corsair DIMMs in an Asus P4P 800 Deluxe motherboard—no longer boots. It was fine until the day my son used it without opening the door to the cabinet that it’s stored in. Now when I try to start it, I get an error saying “CPU Test Failed” and the machine won’t boot. I’ve switched the CPU out with a known good 2.8GHz Pentium 4 (tested in a second PC), to no effect. I have no way of checking the RAM as the second machine we have uses different RAM. Is there a way to check the motherboard? Or is there a way to check the power supply with a multimeter? I’m on a very tight budget so I’m going as cheap as possible.

In the Doc’s experience, Asus’s “CPU Test Failed” error message seems to be a catch-all for any CPU-related problems, including power, RAM, and cooling issues.

Since you know the second CPU is good, we’ll look for the fault elsewhere. The Doc’s guess is the PSU. A 5-year-old PSU when suddenly stressed-out with heat could very well fail. You could use your multimeter to look at each of the power rails (12 volt, 5 volt, and 3.3 volt) to see if anything is out of order. But it may be easier to swap the PSU from the second machine into the first one to see if it boots.

The other possibility is bad capacitors. The vintage of the board puts it right in the time period when the industry was using capacitors with a faulty electrolytic formula. That’s a story in itself, but for now, open up the case, grab a good flashlight, and look closely at the capacitors on the board (check the picture to see what to look for). If any of the caps are bulging or leaking, you likely have a failed capacitor. Usually bad capacitors result in a failure to boot or POST. You can actually buy replacement caps but you need to be handy with a soldering iron if you’re going to attempt a repair. It’s probably more cost- and time-effective to replace the whole motherboard—though by this point, given the age of the machine you’re working with, it might be time for a whole new computer.

SUBMIT YOUR QUESTION Are flames shooting out of the back of your rig? First, grab a fire extinguisher and douse the flames. Once the pyrotechnic display has fizzled, email the doctor at doctor@maximumpc.com for advice on how to solve your technological woes.