Replace soldered DC power jack

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martyyn

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# 173582 28-May-2015 11:27

I've got an old laptop which is not charging or powering up. I've tested the power supply which is fine so bought a new power jack.

I've just pulled it apart but my trusty 40W soldering iron cannot melt the solder between the jack pins and the motherboard. It's only a Jaycar one I bought for doing a car stereo install last year. It's heating ok and melts the roll of solder I have so am I missing something ?

There also looks to be some damage to the motherboard itself. Around the pins to the DC jack it looks like dark brown molasses (in colour and it's glossy) but it's also rock hard. I cant scratch it off at all. I'm wondering if the faulty jack has damaged the board.

Any ideas on how I confirm it's the jack which is faulty without being able to take it off ? There must be somewhere on the board I can plug a multimeter in to.

Thanks

mdooher

Hmm, what to write...
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# 1313373 28-May-2015 11:46

I suspect you have not formed a solder bridge to carry the heat from the iron to the board.

So normally you tin the end if the iron and then touch it to the connection and feed a little extra solder into the gap, this will allow the heat to transfer to the existing solder and melt it.

Matthew

richms

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# 1313382 28-May-2015 11:53

It will be a multilayer board with signifigant groundplanes, so the chance of a toy iron heating the lead free solder hot enough to melt without totally baking the surroundings is very low.

Take it to a properly equiped workshop to get it done. No way with what you have.

Richard rich.ms

martyyn

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# 1313396 28-May-2015 12:05

Thanks to you both. It was just something I wanted to have a play with so no harm done in not being able to do anything.

surfisup1000

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# 1313437 28-May-2015 13:03

I recently replaced the dc jack on my lenovo (thinkpads are not what they used to be, my 2nd keyboard needs replacing again as the keys fail) .

The dc-jack is actually mounted on a little removable board -- so I just purchased a new DC board from ebay for 10 bucks or something, and replaced the board. All good now, check if yours is similar.