Caught a tiny mistake in a power supply that had me stumped for 2 days

Was fixing this old Dell monitor power supply from 2012 and kept getting no output. I checked all the big stuff like caps and diodes but it was a cracked solder joint on a tiny resistor near the optocoupler. Took me 2 hours with a magnifying lamp to spot it because it was hidden under some glue. Anyone else ever wasted time on something that small?

3 comments

3 Comments

paigep2010d ago

Ha, been there so many times my magnifying lamp has a permanent imprint of my forehead on it... spent three hours once chasing a short in a printer power board only to find a microscopic bit of solder bridging two pins on a chip that looked fine under normal light. The glue tricking you is the worst too, like the board is actively hiding things from you. Good lesson though, you start trusting nothing and checking everything after a couple of those...

casey1610d ago

Did you happen to catch that recent YouTube video from the repair guy who found a cracked resistor under a big blob of glue that was practically invisible? I saw it last week and it reminded me of how often glue gets used to hide real trouble. That stuff is a nightmare, especially when it hardens and turns yellow over the years. Makes you wonder if they put it there on purpose to drive us crazy.

the_jana10d ago

Man that glue trick is the absolute worst, I've had it hide more than a few bad joints over the years. Your story about the monitor power supply hits close to home, I spent a whole weekend on an old TV board once only to find a hairline crack under a similar blob of yellowish glue. The magnifying lamp is basically a permanent fixture on my desk now too, can't trust anything after getting burned like that a few times. It's funny how the smallest stuff ends up being the biggest headache, but you're right that it teaches you to double check every corner. Sounds like a solid fix though once you finally spotted it, those are the wins that keep you coming back.