Successful Power Supply Transplant

Successful Power Supply Transplant

I’d written recently that I suspected the power supply in my desktop production PC was too anemic. I just replaced it, and all the problems have gone away!

That machine, an Athlon 2000+ with 512MB of RAM, had been flaky before when it had a 330W power supply in it and I put in a new video card. The new video card sucked down power in great quantities than the old card; you could tell the system was straining because the video display would dim whenever the hard drive was accessed while playing the World of Warcraft alpha. Putting in the more powerful supply–an Antec Trupower 430–seemed to fix the problem. I did notice at the time that the +5 voltage rail was not quite 5 volts, but it was within 5% of spec so that was OK.

Over the year I added more memory, additional hard drives + RAID controller, and a DVD-Writer. I added a couple more cooling fans too. The first sign of trouble was a sudden refusal to boot up with the keyboard functional if I had the computer off overnight. The problem got progresively worse to the point that once the computer was warmed up and stable, I just never turned it off. Then I had bootup problems with the primary HD, and eventually replaced it. When I had it plugged into the system, it functioned sporadically and was not always detected. Eventually I got it working, and noticed that there seemed to be a pattern: the computer had to “warm up” before it would reliably detect all the drives in the system and boot clean. Until the computer had been on for 10 minutes, any drive operations were going to be sporadic.

I recalled also that I had trouble burning DVDs with a very slick Plextor DVD writer. It would function, then after burning halfway through it would poop out and stop working. Very frustrating. Could both these problems be related to the power supply? They were bizarre enough to be so.

For example, the warming up issue: it takes a while for components to heat up and deliver stable power. A good power supply has no such trouble. A bad power supply may not reach stability, or an excessive drain on it will disrupt its ability to keep up. It’s always ‘out of breath’, so to speak. It finally really kicked the bucket yesterday, when I started experiencing random rebooting and lockups. When dropping into the BIOS, i saw that the +5 rail (responsible for supplying power to hard drives and interface cards) had fallen to a precipitous 4.3-4.5 volts. This is way too low.

I put in the new supply today, a “Mad Dog 600W” from CompUSA. It’s cool because it’s targeted at enthusiasts and is mirror-finished, with a pushbutton in th eback to select the level of fan speed, AND it has modular cables so you just have to plug in what you need. The two circuits are marked also, so I have three drives plugged into one circuit, and the RAID plugged into the other. For the big test, I just turned the thing on without warmup to see if it would boot. No problem… booted right into Windows without a hiccup or complaint. I also noticed that the screen seemed a bit brighter and more solid than before, and the +5 rail was a solid 5.0V under full load. The video output signal may be tied to the +5 rail for its voltage signal reference, so it probably is brighter overall if that’s the case.

I hope this PSU sticks it out. The old 430W might still be good for a lighter-weight system…we’ll see.