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    Stubborn solder won't leave hole!

    I've managed to remove all of the bad caps from my MB and now I'm clearing the holes of solder, but there is one hole in particular that the solder refuses to leave. I'm using a de-soldering pump, and most holes clear with one shot. I tried braid, and using a pin to clear the solder initially to see which method worked best for me, but didn't have any success using those techniques, so I settled on the pump as it works great for me.

    With the hole in question, I once again tried braid, and sticking a pin down the hole to make sure there were no cavities devoid of solder in there, but the solder still won't budge.

    I don't suppose anyone has an idea why this might be, or what else I could try? This one hole is really stating to wear my patience thin!

    #2
    Re: Stubborn solder won't leave hole!

    Is this a Pb free board?
    What solder somposition are you using, have you tried adding fresh solder to the hole?

    Sounds contradictory when all you want to do is to remove the solder, but this causes the new solder to mix with the old and via the deoxidant effects of the flux in your solder, it cleans the joint and the molten solder. Bringing impurities to the surface to be burned off or picked up by your wick.
    All in turn reducing the surface tension of the joint and causing increased wetting, allowing the solder to flow where you want it to. Onto your wick.

    Does your wick have a good amount of flux in it?
    What sort of desoldering gun are you using, just a solda-pult type hand pump, a bulb, or a Ratshack style bulb attached to a hollow tip "desoldering" iron?

    Also, the idea of the stainless steel pin isn't to remove the solder from the hole, but to push it aside while molten, leaving a through hole for your replacement/new component lead. This is achieved where by you apply heat to the through hole, insert the pin through the hole of molten solder, then remove heat while leaving the pin in the hole till it's cool enough that once removed the solder doesn't stick to the stainless steel. Make sure it's not plated and that it is indeed stainless.

    I should also add that you do need to be careful that you use a pin that can go fully through the hole and out the other side without reaching the hilt of the pin or pick. This is to be avoided, as it can lift the pad, or worse yet, pull out the "plated/sleeved via".

    Lastly, always keep your heat time on the joint to a minimum. Enough heat and thermal mass of tip+iron, such that you only work the joint for 2sec at a time. Any longer and you risk lifting pads, tearing/lifting traces/tracks, etc.. If you have to leave it there longer, either your tip is too small, your iron, or your heat setting. But you don't want it so hot that it boils like water drops on a seething hot griddle.

    Hope that helps.
    How to properly apply thermal grease - Y_not's way.

    Comment


      #3
      Re: Stubborn solder won't leave hole!

      Add 60/40 solder to both sides of the hole, then wick away with 0.50" diameter or less braid.
      "We have offered them (the Arabs) a sensible way for so many years. But no, they wanted to fight. Fine! We gave them technology, the latest, the kind even Vietnam didn't have. They had double superiority in tanks and aircraft, triple in artillery, and in air defense and anti-tank weapons they had absolute supremacy. And what? Once again they were beaten. Once again they scrammed [sic]. Once again they screamed for us to come save them. Sadat woke me up in the middle of the night twice over the phone, 'Save me!' He demanded to send Soviet troops, and immediately! No! We are not going to fight for them."

      -Leonid Brezhnev (On the Yom Kippur War)

      Comment


        #4
        Re: Stubborn solder won't leave hole!

        Originally posted by y_not View Post
        Is this a Pb free board?
        What solder somposition are you using, have you tried adding fresh solder to the hole?

        Sounds contradictory when all you want to do is to remove the solder, but this causes the new solder to mix with the old and via the deoxidant effects of the flux in your solder, it cleans the joint and the molten solder. Bringing impurities to the surface to be burned off or picked up by your wick.
        All in turn reducing the surface tension of the joint and causing increased wetting, allowing the solder to flow where you want it to. Onto your wick.

        Does your wick have a good amount of flux in it?
        What sort of desoldering gun are you using, just a solda-pult type hand pump, a bulb, or a Ratshack style bulb attached to a hollow tip "desoldering" iron?

        Also, the idea of the stainless steel pin isn't to remove the solder from the hole, but to push it aside while molten, leaving a through hole for your replacement/new component lead. This is achieved where by you apply heat to the through hole, insert the pin through the hole of molten solder, then remove heat while leaving the pin in the hole till it's cool enough that once removed the solder doesn't stick to the stainless steel. Make sure it's not plated and that it is indeed stainless.

        I should also add that you do need to be careful that you use a pin that can go fully through the hole and out the other side without reaching the hilt of the pin or pick. This is to be avoided, as it can lift the pad, or worse yet, pull out the "plated/sleeved via".

        Lastly, always keep your heat time on the joint to a minimum. Enough heat and thermal mass of tip+iron, such that you only work the joint for 2sec at a time. Any longer and you risk lifting pads, tearing/lifting traces/tracks, etc.. If you have to leave it there longer, either your tip is too small, your iron, or your heat setting. But you don't want it so hot that it boils like water drops on a seething hot griddle.

        Hope that helps.

        I did try adding a bit of fresh 60/40, but just to one side of the hole.

        I have been fluxing the hell out of my wick!

        I'm using a cheap plunger type de-soldering pump from ebay - the kind where you press the button and the plunger flies back creating a vacuum.

        The pin idea I tried was simply pushing it all the way through, and back out again, in the hope that it would dislodge any air, so that all the solder in the hole would melt on contact.

        The MB is not Pb free as far as I can tell - the solder melts fairly easily with a cheap 40W iron (again from ebay).

        I do try to keep heating time to a minimum, but have to admit sometimes it's been a little longer than 2 sec - perhaps up to 10 in some cases. So far I don't think I've damaged any pads, although one of the corners got lifted up on one, but that was "intentional", as I thought I had solder in contact with a trace, so I lifted it with a pin only to find it was a pad! Hopefully since it's just a corner it should be ok?

        I'm still learning when it comes to soldering!
        Last edited by pinknoise71; 05-13-2013, 06:49 PM. Reason: typo

        Comment


          #5
          Re: Stubborn solder won't leave hole!

          Originally posted by mockingbird View Post
          Add 60/40 solder to both sides of the hole, then wick away with 0.50" diameter or less braid.
          Thanks. Going to try doing the other side too now.

          Comment


            #6
            Re: Stubborn solder won't leave hole!

            Still no joy

            I tried the other remaining holes and it's the same story. It can't be a coincidence. I did leave the hard to get to holes till last. They are all in awkward to get to places that I could not reach with the tip of the de-solder pump, so I'm using a short piece of electrical flex outer insulation as an extension - it fits nicely over the de-solder pump nozzle and gives me an extra few mm reach. It worked fine at first, so I doubt that's the problem.

            I may give up on it and try the braid again later on today after I get some sleep. I'm not sure if I'm doing something wrong with the braid as I can't get it to work. Are you supposed to stick the braid in the hole and follow the solder down?

            Comment


              #7
              Re: Stubborn solder won't leave hole!

              Sleeping on it is always a good thing... well, not "on it" that'd be pokey & hurt, scratching your skin with those pokey leads.... likely cause bleeding.

              But seriously, the brain processes information for the day as you sleep, catalogs it and commits learned data to memory.
              It's kinda like a cron job for *nix.

              That's why when you "sleep on it" and you get up in the morning, suddenly you can do it right, or you come up with a solution.

              Learned that from a study on sleep and its effects on the brain's motor skills & problem solving. In a nutshell that is.
              THANK YOU NPR!!!
              *IIRC, I partially skipped lunch to finish listening to it.
              How to properly apply thermal grease - Y_not's way.

              Comment


                #8
                Re: Stubborn solder won't leave hole!

                Well, after a good night's sleep I tried the de-solder pump and braid again without any luck. Then I remembered I'd seen a paperclip on the floor in our garden store room, so I went and found it. It turns out it was just the right size, and I've just cleared two of the difficult holes!

                Not sure if it's stainless, but it works, so I'm happy

                Thanks for the encouragement and advice y_not and mockingbird!

                Comment


                  #9
                  Re: Stubborn solder won't leave hole!

                  Job done! 44 holes cleared in total. Now to check the work and make sure no traces have been compromised and no inadvertent connections made.

                  Comment


                    #10
                    Re: Stubborn solder won't leave hole!

                    Here are a few pics I got of the more iffy de-soldered holes.

                    The first two are examples of the most damaged pads, and the last two may have unwanted solder bridges.

                    I think I may have got away with it... what do you guys think?
                    Attached Files

                    Comment


                      #11
                      Re: Stubborn solder won't leave hole!

                      You really need to get a better soldering iron...

                      Or if you already have a good one, stop using a needle point tip...

                      I can do a better job than that with a $6 piece.
                      "We have offered them (the Arabs) a sensible way for so many years. But no, they wanted to fight. Fine! We gave them technology, the latest, the kind even Vietnam didn't have. They had double superiority in tanks and aircraft, triple in artillery, and in air defense and anti-tank weapons they had absolute supremacy. And what? Once again they were beaten. Once again they scrammed [sic]. Once again they screamed for us to come save them. Sadat woke me up in the middle of the night twice over the phone, 'Save me!' He demanded to send Soviet troops, and immediately! No! We are not going to fight for them."

                      -Leonid Brezhnev (On the Yom Kippur War)

                      Comment


                        #12
                        Re: Stubborn solder won't leave hole!

                        Originally posted by mockingbird View Post
                        You really need to get a better soldering iron..
                        Couldn't agree more.

                        Case in point to OP...
                        The round pads in your photos show clear signs of either not enough heat to start with, or simply a lack of reserve heat/thermal mass in the tip+heater core to maintain consistent temperature. So you get that dirty, pitted, pot metal kind of look to the solder. Where it's half heated and cools at irregular rates throughout the solder mass.

                        You should check out Dave Jones' EEV blog videos on soldering.
                        He doesn't cover de-soldering, at least not what I have found.
                        But what he does cover in his basic solder tutorials gives you more than enough info on proper heat control and tip thermal mass for the work area + component.

                        Also look @ the Pace solder how-to videos on YouTube. They're from the 80's, but aside from the shameless plugs on their product offering, there's a loooot of good info in there. They cover thermal mass quuuuiiiittteeee extensively.

                        I have a transcript I did of the useful parts that I need to post.
                        In fact, me thinks I'll go do that right now.
                        How to properly apply thermal grease - Y_not's way.

                        Comment


                          #13
                          Re: Stubborn solder won't leave hole!

                          Originally posted by mockingbird View Post
                          I can do a better job than that with a $6 piece.
                          That's about how much it cost me

                          Anyway, like I said, those were the worst examples - the tricky ones to de-solder, and I must have heated up those pads 50x or more

                          I've attached an example of a better de-solder below.

                          I do want to get myself a good temp. controlled iron eventually.

                          I also just realized that the type of de-soldering pump that I used is not recommended for clearing holes - I could have sworn it was! Either way, it's done now.

                          I also soldered in the new caps, which went better than I was expecting, and I'll put the PC back together tomorrow and see if it posts.

                          Thank you both again for the feedback!
                          Attached Files

                          Comment


                            #14
                            Re: Stubborn solder won't leave hole!

                            What soldering iron did you use and how easy was it to remove the capacitors.
                            http://www.hse.gov.uk/pubns/indg305.pdf

                            Comment


                              #15
                              Re: Stubborn solder won't leave hole!

                              Don't worry so much about clearing it out. I hope you haven't damaged anything with heating it so many times. If I can't clear the hole I just insert my new part right in and not worry about it and add a little bit more solder. I've never had a problem yet.

                              y_not gave you some excellent instructions.

                              Comment


                                #16
                                Re: Stubborn solder won't leave hole!

                                Originally posted by mutant View Post
                                Don't worry so much about clearing it out. I hope you haven't damaged anything with heating it so many times. If I can't clear the hole I just insert my new part right in and not worry about it and add a little bit more solder. I've never had a problem yet.

                                y_not gave you some excellent instructions.
                                Sounds like a good plan mutant, better to leave it working than to make it perfectly clean & brand new looking, but ruin the board. It doesn't make much sense if you have to fight it otherwise, when all you're going to do is just put more solder back in the hole anyway
                                I figure so long as you can get as much as possible out without hosing the board, and if going any further means potentially causing damage, then just stop and put the new cap in and call it a day.

                                This is where BossStooge's needle method is da'bomb diggity!!!
                                It may not be as "pretty" as some of us OCD types may like, but hey, it works.
                                And so long as the joint is good and it looks good on the outside, who will know, right?

                                It's not like I ever try to hide things under the rug, I always try to do my best, no matter what I'm doing. But sometimes compromises have to be made, it's life... it bites, but you do what you have to do sometimes. Reckon?

                                BTW mutant sir, thank you for the compliment.
                                I'm just starting out myself, but I'm a crazy fast learner.
                                So what I pick up from the head honchos & the masters of the industry, I hold on to and gladly pass on.

                                I am no master of this stuff myself, not even close. I am but a tiny grasshopper.
                                But knowledge is knowledge.
                                It doesn't matter if one has mastered it, or done it themselves. What matters is if others have successfully done so using the same knowledge & practices. Then surely it's sound knowledge, that is, until one finds a better way on their own quest to mastery & perfection.
                                Sensei says: "wax on, wax off"
                                How to properly apply thermal grease - Y_not's way.

                                Comment


                                  #17
                                  Re: Stubborn solder won't leave hole!

                                  Originally posted by Fast Alpha View Post
                                  What soldering iron did you use and how easy was it to remove the capacitors.
                                  If I remember correctly it was a Silverline (40 W).

                                  Looks like I did screw up the board during the process somehow. It gives me a beep code that means either a memory or a GFX problem. I'll have to try swapping RAM about a bit more and a different GFX card when I get a chance, but I have a feeling the board is toast.

                                  Comment


                                    #18
                                    Re: Stubborn solder won't leave hole!

                                    Originally posted by pinknoise71 View Post
                                    Looks like I did screw up the board during the process somehow. It gives me a beep code that means either a memory or a GFX problem. I'll have to try swapping RAM about a bit more and a different GFX card when I get a chance, but I have a feeling the board is toast.
                                    Remember to use "known working parts". Also, check the VRMs to be sure you don't have a CPU killer, as instructed here:

                                    Identifying a CPU killer (ahead of time) help
                                    Akor's VRM checking procedure
                                    How to test a voltage regulator - "retiredcaps" method

                                    Yeah, if that doesn't fix it. I'd say all that pad damage was just too much, taking beyond its limits.

                                    At that point you're going to be looking at pad & possibly track repair. Inspect it with a high powered loop and so how much damage you're really dealing with and if there's any damage to the traces themselves, around the repair area, or if it's just the pads. Get some light in there and see if your via plating/sleeve is intact.
                                    Look for lifting, delamination, etc..

                                    There are instructions on here as to how to repair the damaged caused by soldering rework failures. At the very least it'd be good practice for you, for the next board that you legitimately damage once you have better honed your soldering/de-soldering skills & hopefully have better equipment.

                                    What was wrong with the board in the 1st place, what board is it & what caps did you replace & where?
                                    Are there any questionable brands/series+date range remaining?
                                    Last edited by y_not; 05-24-2013, 03:22 PM. Reason: Added links.
                                    How to properly apply thermal grease - Y_not's way.

                                    Comment


                                      #19
                                      Re: Stubborn solder won't leave hole!

                                      It's an Abit IC7-MAX 3. It all started when I took my PC to bits to clean the CPU heatsink which had gotten clogged up with crud (I usually clean it annually), and I failed to seat the heatsink properly, so the CPU got fried. I got a new CPU for it, but while putting it back together I noticed some of the caps swelling, and a couple had ejected electrolite over the board.

                                      With the new CPU it was still working fine apart from the very occasional re-boot for no apparent reason. In all I think it was 24 caps I replaced (two types - the larger ones you can see on the board in the picture in the thread I linked to above, but not the huge ones under the shield which seem fine). There are a few other details in my other thread here.

                                      Many thanks once again for the links and great info y_not!

                                      I'll have to put it on the back burner for a bit as I'm quite busy at the moment, but when I get some time I'll have a tinker.

                                      Comment


                                        #20
                                        Re: Stubborn solder won't leave hole!

                                        For hard to clean holes you might try QuikChip that melts at a lower temp. Sometimes my
                                        Den- On desoldering tool has difficulty. At that point put the board in stand, desoldering tool on one side and a soldering iron on the other always does the trick.

                                        Comment

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