Connect with us

Soldering problem

Discussion in 'Troubleshooting and Repair' started by ventsyv, Dec 3, 2014.

Scroll to continue with content
  1. ventsyv

    ventsyv

    29
    1
    Dec 3, 2014
    I'm trying to replace my laptop's power connector. I ordered the replacement plug, pulled the motherboard out, but am unable to remove the old connector. I'm using a cheap 60W soldering iron I got on Ebay. I don't have a heat gun. Do I need one? Any suggestions?
     
  2. (*steve*)

    (*steve*) ¡sǝpodᴉʇuɐ ǝɥʇ ɹɐǝɥd Moderator

    25,477
    2,820
    Jan 21, 2010
    Show us an image of the board and the connector
     
  3. ventsyv

    ventsyv

    29
    1
    Dec 3, 2014
    Last edited: Dec 25, 2014
  4. Gryd3

    Gryd3

    4,098
    875
    Jun 25, 2014
    I can't say the 'right' way to do it, but I can tell you what I would do.

    Soldering Irons work much better when the tip is clean...
    I have a ball of brass shavings (Like steel wool) that I clean the tip off on, but in a pinch, I have used damp paper-towel.
    Additionally, solder will melt when it gets hot enough... so you need one of two things... a hotter iron, or a better connection.
    A better connection can be achieved by using a clean tip, but also attempting to put more surface area of the iron on the solder you are attempting to melt. (Different tip shapes help greatly here too...)
    If you have trouble here, it may sound counter intuitive, but you could try to add a tiny bit of solder. The new blob of liquid solder will help transfer heat to the dry solder on the board. Hopefully this will allow just enough extra heat to transfer to melt the solder on the board you are working on.

    Additionally, having a solder wick, or solder pump here is going to be a requirement... Trying without is asking for trouble.

    (If you can... find a board to practice with first!)
     
  5. ventsyv

    ventsyv

    29
    1
    Dec 3, 2014
    I think the tip is fairly clean (i used paper towel to clean it) but you are right that it is probably not making good contact. I think it's hot enough it melts the solder wire just fine. So u dont think it's a special type of solder that melts at higher temp?
     
  6. chopnhack

    chopnhack

    1,573
    354
    Apr 28, 2014
    Sometimes the lead free solder is harder to rework. Do you have any flux gel or a flux pen you can use?
     
    Gryd3 likes this.
  7. Gryd3

    Gryd3

    4,098
    875
    Jun 25, 2014
    Different solder melts at different temperatures, but I can't see that stuff being 'special'... The components on the board also need to undergo the heat required to melt the solder depending on the soldering method used, so it would make sense to pick something that didn't require the board to spontaneously combust when melting the solder.

    When the tip is clean, it should have a sort of shiney property to it. When it gets discoloured or dull, then it is dirty or beginning to oxidise. Wiping it on a damp sponge for example will help pull off excess solder and some gunk that has built up. This is done with the iron on. If it gets really bad... you may need to go as far as repairing the tip by removing oxidisation with sandpaper, and re-tinning the tip.
    You will typically only use your iron with a 'tinned' tip. This is a little bit of solder, or tinning compound that very lightly coats the soldering iron to prevent it from oxidising. Of course, this also helps heat transfer.

    One word of warning for this type of work... If it does not seem like the solder is melting, don't simply hold the iron on. The copper traces on some boards can be sensitive to excessive heat, and doing so will cause the copper to separate from the board... this results in broken pads and traces which can be very difficult to repair.
     
    chopnhack likes this.
  8. chopnhack

    chopnhack

    1,573
    354
    Apr 28, 2014
    Agreed, and pushing harder does not help transfer heat any better :rolleyes: don't ask me how I know!

    Traces start to lift as the adhesive that is used to fix the copper sheet to the substrate melts before the solder does.

    The few boards I have worked on or scavenged were very hard to get started - I noticed the solder was not as shiny so that it was either no lead solder or the solder was perhaps contaminated or overcoated with something. Either way, the flux made it much easier to work with. On some really stubborn spots, I took some fine sandpaper to the area, followed by a liberal cleaning with flux. Then the solder would run well.
     
  9. KrisBlueNZ

    KrisBlueNZ Sadly passed away in 2015

    8,393
    1,270
    Nov 28, 2011
    I have a limited amount of experience here but I have some suggestions.

    Motherboards are multi-layer boards - six or more layers; two on the outside and four or more in the middle. This means it takes quite a lot of energy to raise the temperature enough for all of the solder to melt and release the tag.

    Start by destroying the plastic parts of the connector so each tag can be removed independently. Keep as much metal intact as possible. This speeds things up a LOT. Then to remove a tag, apply a soldering iron with a decent power capability - 50~60W is good - directly to the actual tag, using the side of the soldering iron bit to transfer the heat as efficiently and quickly as possible to the longest side of the tag itself.

    If possible, use a soldering iron on each side of the board, simultaneously - put the board in a vice using some kind of padding, e.g. folded up rags - clamp it close to the connector so it doesn't flap around, but not so close that it draws heat away - and/or ask a friend to help.

    Make sure the soldering iron bit is thorougly tinned before you start, so it will conduct heat onto the tag along the whole contact area. Use solder (apply it to the tag) to help with the heat flow. You can also apply solder to the corner formed by the board and the tag, to get it to flow onto the board (if it doesn't already).

    Lead-free solder has a high melting point and makes things difficult, but you can get special low-melting-point solder (Chip Quik and other brands) that will mix with the existing solder and lower the melting point. You will ultimately have to melt all of the original solder to get this stuff to mix with it, but it will make things a lot easier because it will flow and transfer the heat around to areas of original solder that you can't get direct access to.

    Pull the tag outwards using steady pressure but don't use pliers; these will draw heat away from the tag. If possible, attach some thin but strong wire to it. Bend part of the tag over to provide a place to loop the wire around. You can attach a brick to the wire, or attach it to a bit of thick cardboard or leather and pull it with your mouth.

    When the tag is out, get the solder out of the hole using a vacuum solder sucker, a squeeze-bulb solder blower, or ideally, a desoldering iron. Try to remove all the tags in quick succession.

    That's the end of my advice. Others will have more helpful ideas.
     
  10. ventsyv

    ventsyv

    29
    1
    Dec 3, 2014
    I tried tinning the tip but the solder does not melt well, it stays as drops on the tip of the soldering iron. I don't know if it had reached operating temperature but it was definitely hot, the tip was slightly red.

    I'm tempted to get a new soldering iron, maybe something like this:
    http://www.ebay.com/itm/390950226201?_trksid=p2060778.m1438.l2649&ssPageName=STRK:MEBIDX:IT

    I don't want to spend a lot of money, but I'll probably end up using it occasionally, is this a good value for what I need?
     
  11. KrisBlueNZ

    KrisBlueNZ Sadly passed away in 2015

    8,393
    1,270
    Nov 28, 2011
    If the tip is slightly red, the soldering iron is FAR too hot!

    That item on eBay is a complete soldering/desoldering station! If it performs like a name-brand one, it's an incredible bargain! So I suspect it won't. But it might still be enough for this job. I can't say - but I will say what I usually say to people who are considering buying from eBay: Caveat emptor! (Buyer beware.)
     
    chopnhack likes this.
  12. ventsyv

    ventsyv

    29
    1
    Dec 3, 2014
    This is incredibly frustrating. I cleaned the tip with sandpape, heated the iron up, tinned the tip then unplugged it so it doesn't get too hot, but still no luck. I removed all plastic from the connector as well.

    How can I tell if the ironing station performs as it should? The specs sound very good to me and since it's probably made in China, i suspect the 80-20 rules apply, 80% quality 20% lower cost.

    What would a brand name station cost?
     
  13. ventsyv

    ventsyv

    29
    1
    Dec 3, 2014
    I managed to remove the old connector I'm now trying to clean the connection points.
     
  14. chopnhack

    chopnhack

    1,573
    354
    Apr 28, 2014
    Good job! Go slow.
     
  15. ventsyv

    ventsyv

    29
    1
    Dec 3, 2014
    What's the proper way to di that? I'm using thw iron to melt the solder then a very thin screwdriver to make a hole. Thats probably super hacky way to do it right?
     
  16. chopnhack

    chopnhack

    1,573
    354
    Apr 28, 2014
    I would not be making new holes in that board given its a multi layer board, you could inadvertently short or puncture a signal layer trace.

    Are you just trying to re-open the hole where the old part was in? Did the solder reflow over the hole when you pulled out the through hole component?
     
  17. ventsyv

    ventsyv

    29
    1
    Dec 3, 2014
    Not putting new holes, just opening up the old ones, solder reflowed over them.
     
  18. KrisBlueNZ

    KrisBlueNZ Sadly passed away in 2015

    8,393
    1,270
    Nov 28, 2011
    Sanding the tip is probably not a good idea unless it's a really cheap and nasty one. Good quality ones are plated AFAIK and you shouldn't sand the plating off!
    Good!
    I use a different 80/20 rule for cheap Chinese products: 80% of the time it will last less than 20 days :) Just kidding. There's a lot of variation and luck involved. You might get a lemon that's useless from day one, or you might get a unit that works fine and lasts for years. To paraphrase Forrest Gump, "eBay's a box of chocolates... you never know what you're gonna get!"
    Hakko are widely used and recommended. I used one of their older models, before they went to this weird yellow and blue colour scheme, and it was very good. http://www.hakko.com/english/products/desoldering/desoldering_tool/ and replacement tips are available through Mouser.

    As for other reputable brands, have a look at these offerings from Farnell (UK). I don't know where you can buy them in the U.S. but a Google search should tell you. http://uk.farnell.com/webapp/wcs/st...ICE&pageSize=25&beginIndex=1&showResults=true

    Yeah, it is. You need to melt the solder all the way through the hole and clear it out in one operation. A blast of air is a good way. You can get desolder vacuum pumps (aka solder suckers), desoldering bulbs that squirt a jet of air, and desoldering/rework stations like the one you found, which have a vacuum pump and a hollow tip.

    You could also try using a piece of plastic tubing with a rubber grommet or similar around the end of it, to make an airtight seal to the board around the hole. Blow into the tube, or attach it to a bellows or pump of some kind - perhaps a tyre pump. Use your imagination!

    Edit: If there's one hole you can't clear out, but the others are OK, you can fit the replacement connector - just melt the solder in the stubborn hole and shove the connector into position.

    Also... Try to keep soldering operations as brief as possible and allow the board to cool (don't forcibly cool it) between operations. Otherwise the heat will build up and spread and can damage the board and even nearby components.
     
  19. ventsyv

    ventsyv

    29
    1
    Dec 3, 2014
    Desoldering pump is in the mail, but i ust can't wait. I have a small handheld ball pump, I'll try using that.
     
  20. Bluejets

    Bluejets

    4,505
    958
    Oct 5, 2014
    Couple of videos from Youtube...thought they may help also.



     
    KrisBlueNZ likes this.
Ask a Question
Want to reply to this thread or ask your own question?
You'll need to choose a username for the site, which only take a couple of moments (here). After that, you can post your question and our members will help you out.
Electronics Point Logo
Continue to site
Quote of the day

-