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Found a cracked solder joint on a 20 year old PSU that fixed random shutdowns
I've been fighting with this old Dell Optiplex at my shop for weeks - it would just randomly power off during boot, no pattern at all. Finally got out my jeweler's loupe (you know, the 10x one) and spotted a hairline crack around the main power transistor on the PSU board. Reflowed it with my Hakko 888 at 370C and the thing has been running solid for 4 days straight now. Has anyone else run into hidden solder cracks on older power supplies that look fine to the naked eye?
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foster.wade12h ago
Man, that is SO satisfying to hear. I've been there with a few old PSUs and it's ALWAYS the stupid little cracked joint that drives you crazy. I had a Seasonic unit from like 2005 that would only die when it got warm after about an hour of gaming, turned out to be the same thing on a MOSFET leg. You really do need that loupe though, naked eye can miss it every time. Glad you stuck with it and didn't just toss the whole board. That reflow fix is a GAME CHANGER for old gear.
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sarahsullivan8h ago
Exactly, the thermal cycling angle is HUGE here. Those old solder joints get brittle after years of heating up and cooling down, and it only takes one tiny crack to break the circuit when the board flexes just right. I bet if you hit that MOSFET leg with some flux and a quick reflow, it would be back to gaming shape no problem.
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