I love it when what at first appears to be a catastrophe turns out to be no big deal.
Earlier my power went out, just for a minute. Once it came back on I discovered an issue with my file server. It would power up briefly then shut down. It wasn’t even making it into POST, no beeps, no nuthin’. Immediately panic starts to set in as I imagine all of the expensive, time consuming, pain in the ass possibilities. I try it several more times, each with the same result. Then, after I got ahold of myself, I decided maybe it was the power supply, as that seemed the most likely culprit.
So… I retrieved my power supply tester, turned off the power supply, opened up the case and disconnected the 20-pin connector from the motherboard. I plug it into the tester, power it up, and it’s fine. Hmm…
must be the 4 pin connector for the CPU, that’s the only other line I can think of that might keep the computer from POST-ing. Again it tests as good.
Puzzled, I plug the connectors back in and give it another try. Just as before the power LED lights and the fans spin up, but this time, one short beep! Hallelujah! I punch it up on the KVM switch and see this message: CMOS Checksum error. Hmm… could the battery be dead? I pull the battery, grab my multi-meter, and sure enough, it’s dead. Completely, 100%, graveyard dead. Happily, I have a spare battery on hand. I replace the battery and it boots right up, happy as a clam.
Hooray for successful trouble-shooting (and a bit of luck). The “experts” on the internet seem to be split as to whether or not a dead CMOS battery can stop a computer from powering up. Some say yes, some say absolutely not. Well, I now know for a fact that it can. So, if you have a computer that powers up then right back down and isn’t giving any beep codes, test the power supply and the CMOS battery before letting visions of fried CPUs, dead motherboards, or bad RAM dance through your head.