Pro tip: Check the PSU before you blame the motherboard, like I did on a Dell Optiplex 9020 last Thursday.

I spent 2 hours swapping parts in a client's machine only to find a bad 450W power supply was causing the random shutdowns, so what's your go-to diagnostic step for power issues?

3 comments

3 Comments

aaron1972mo ago

Been there, done that. I fried a good motherboard once by not checking the PSU first. My go-to now is a cheap power supply tester. It saved me last week on an old HP that wouldn't post.

the_kim2mo ago

Those testers can give a false sense of security though. They only check if the rails are live, not if the power is clean under load. A cheap unit can pass the tester but still send dirty power that slowly cooks components. Sometimes the old paperclip test and a multimeter for voltage ripple tells you more.

grant.margaret9d ago

Hey @aaron197, did you ever check if that HP had a proprietary pinout on the motherboard connector? I found out the hard way that some of those old office desktops swap the ground and 5VSB pins around compared to standard ATX. A regular tester would show everything fine, but plugging in a standard PSU would just fry the board instantly. Had to track down the service manual and map each wire with a multimeter before I felt safe swapping a new unit in. Have you run into any weird pinouts like that on your old HPs?