TIL a dead CMOS battery on a 12 year old Dell can fake a dead motherboard
A guy brought in a Dell Optiplex 790 from his insurance office in Tempe that would not post at all. No beeps, no lights, fans spun for two seconds then stopped. I quoted him a board swap because that is what it looked like to me, and he said he would think about it. Before he left I pulled the coin cell just to test it and it read 0.4 volts, basically dead. I swapped in a fresh CR2032, cleared the CMOS, and the thing booted straight to Windows like nothing ever happened. He paid me $60 and I felt silly for almost selling him a motherboard he did not need. Now I check that battery first on anything older than 8 years, it takes 30 seconds and has saved me from misdiagnosing at least 4 machines since. What is the dumbest thing you almost replaced before checking something basic first?