On Mon, Dec 8, 2008 at 10:44 AM, Virchanza wrote: > > All good things must come to an end, and every computer claps out > eventually. Aside from the mechanical aspects of the computer, the electrolytic capacitors (used on the motherboard switching power supply for the CPU/memory/northbridge voltage) are generally the ones that go first. Electrolytic caps have a limited lifetime that's worsened by heat. Good caps have an MTBF of 2,000 hours, but that cuts in half at the temperatures that exist in a PC case near the CPU. I used to have a stack of CPU and motherboards that were replaced due to capacitor bulging/leaking and a few bags of replacements. When I needed another workhorse machine I'd grab the soldering gun (the negative is usually soldered to a huge ground plane - no thermal relief because the additional resistance/inductance wasn't good for the switching supply) and replace all the electrolytics. Get another few years out of a motherboard for $20 for the nicer (higher heat, longer lasting) electrolytics. Nice thing about these caps is that when they failed it was obvious. A lot of electrolytics fail without visibly changing, and there are a lot of 'good' motherboards out there replaced due to normal component aging. Of course, there are other aging related failures, but modern chip making and PCB manufacturing has limited things like copper migration on the PCB, or semiconductor migration (and whiskers) in the chips. Thermal cycling is a big deal with the elctrolytics, though, and often they fail in a way that allows them to keep operating if already on (with increased ripple, which can cause its own problems in the logic) but they will be enough out of spec that the switcher won't start reliably if turned off. So... it's a toss up. Regardless, give your PC as much cooling as physically possible - heat is the greatest enemy for electrolytics and mechanical components. -Adam -- Please rate and vote for my contest entry: http://mypic32.com/web/guest/profiles?profileID=50331 -- http://www.piclist.com PIC/SX FAQ & list archive View/change your membership options at http://mailman.mit.edu/mailman/listinfo/piclist