I'm trying to replace a faulty DC power jack on a laptop, and having quite a difficult time with it. At this point, I'm not sure if the problem is with my equipment, or my technique.
Equipment:
- Weller 50w temp controlled iron (max temp: 850f, ETA tip)
- Dremel gas powered iron / hot air gun (this thing)
There are six pads on the underside of the board I need to desolder to remove the old jack. The four on the outside, far as I can tell, only provide mechanical support rather than electrical connectivity.
This is what the board looks like from the top:
And the bottom:
(It's a bit of a mess due to my previous attempts. The black/brown crap is just flux, not char on the board)
It took a lot of messing around to get it out as far as it currently is.
The main problem is that removing the existing solder is proving to be nigh impossible – I've got both some desoldering wick, and a solder sucker.
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The sucker has proven all but useless, the moment I move the iron out of the way to get the sucker in place, the solder has already rehardened.
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The wick kinda works, but it seems to take a very long time to get very little solder absorbed. As in, you can see the faintest hint of silver color in the copper wick.
My technique was to set my iron to max temp (850f), let it get up to temperature (verified on the digital display), add some flux, hold the wick in place on top of the pad and press the tip of the iron into it.
My understanding is that this high temperature is required due to factory solder being trickier to deal with than the stuff you buy on a spool, and also likely to be the lead free kind, which requires a higher melting temperature.
Now the other option I have is the torch/hot air gun, but I don't want to mess around with it too much for fear of scorching the board. Hence why I'm here, asking someone who's hopefully an expert.
How do I tell when my work area is getting too hot?
Given what I've described here, am I doing anything obviously wrong?
Am I missing some crucial piece of equipment to make this job easier?
Best Answer
The jack is faulty, so...
Cut all the plastic away with side cutters, leaving just the metal terminals. Now you can remove each terminal separately.
Hold the circuit board vertically in a vise. Get your iron hot as usual, and apply more solder to the pad to improve heat transfer. Grab a terminal (on its edge to reduce heat transfer) with your pliers, then heat the pad with your iron. The solder should melt quickly, then you simply pull the terminal out of the board.
Finally, use a solder sucker and/or desoldering braid to remove excess solder from the hole.