Tried hot air rework on a stubborn capacitor and learned the hard way

I was fixing a busted power supply from a 2012 Dell desktop last weekend. The capacitor was stuck on the board like it was welded on. I cranked my hot air station to 400C and hit it for a solid minute. Nothing moved. So I kept going another 30 seconds and the whole surrounding plastic connector started melting. Learned that slow and steady wins with these boards. I should have used flux and a low melt solder first to break the connection. Now I'm out a connector and the cap is still half on there. Anyone else have a trick for getting stubborn through-hole caps off without damaging the board?

3 comments

3 Comments

mason_foster6815d ago

Oh man, I feel your pain. I did the same thing on an old Asus motherboard last year with a bulging cap that just would not budge. I had my iron cranked up to like 450C and kept prying at it until the pad lifted clean off the board. Total rookie move. What works for me now is I use a hot air preheater set to around 150C from underneath to warm the whole board first, then hit the cap legs with a soldering iron and some Chip Quik low melt solder. That stuff is magic for breaking those stubborn joints without melting everything around it. Ever try using a solder sucker with a wide tip? That helped me clear the holes easier after the low melt did its job.

smith.ray15d ago

Have you ever tried using a solder wick with flux after you pull the cap out? I find that works better for me than a solder sucker, especially on those tight spots. @mason_foster68's idea about the preheater is smart though, I just use a hot air station on low from a few inches away to warm the board before I go in with the iron. Low melt solder is a game changer for sure, I swear by that stuff now after destroying one too many pads. Just make sure you clean off all that leftover low melt with some fresh solder and wick before you put the new cap in or it'll be a mess.

amyh2114d ago

Wait, you had your iron at 450C? That's insane, I'm surprised you didn't lift the whole pad off the board. @mason_foster68 that must've been gutting to watch that pad just come right up.