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poor mans reballing

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    poor mans reballing

    so, with the advent of me getting a heatgun, I decided to try my hand in reballing, as one time I saw a video online of how it can be done without actual balls, stencils, or anything but a heat gun, iron, braid, and lots and lots of paitence...and a careful hand. I have tons of nforce 3/4/6 boards with bad balls, and this is what I tried, they all failed, but I learned several things

    the old solder has some nasty black shit in it when I braid it off, on all of them. The trick I'm going for is to braid the solder off the board pads and the chip pads, then flux-up the pads, get a tiny dab of solder on each (board pads and chip pads). put the chip back and re-heat it up, try to get them to merge. Mind you these are not balls, but dabs, which is why both of them need a dab, and it will put the chip actually right against the board, and make a small, flat soldered connection. not sure about the heat implications here, with the chip being right up against the board, are we getting a higher chance of getting disconnected pads, even with flux and leaded solder? not sure

    first thing I did was a nforce 2 southbridge, came out REAL easily, popped a pad with the iron trying to braid the old solder off. I turned it up, and actually wetted the tip from then on out, this let the old solder flow more easily into the braid, without putting stress on any of the pads. After destroying the balls on both the chip and board, I realize from there on out, putting 92% isoprobyl on my finger and just rubbing the damn pads gets rid of this black shit left over, I tried q-tips at first with VERY bad results (q-tip hair stuck around pad, tore them off). Then I tried the northbridge, came off pretty easily, still learning. I put the heat gun on high (dual mode gun). Tried to melt some more of the solder on the board pads cause some of it will still dull and well, bad, ended up putting it too long on the board, and warped it, a common problem

    tried then an nforce 4 board nb. Tried heatgun on high, old solder was so crappy the chip still did not come off, and when I finally go it hot enough, not only was some pads ripped when I got the chip off, but there was a panny next to one of the pads that bloated, hissed, and burned, right infront of my eyes, which was pretty cool

    Next was a nforce 6 board, tried the gun on low setting, REALLY close, and eventually I got the chip off without tearing any pads.

    after you braid the old solder off, clean the pads on both the chip and board, what you do is flux an entire area, put a bunch of solder on the tip, and run the solder 'bubble' moved to the bottom of the tip by our friend mr. gravity over the pads, and it pools on each pad. if you do not use flux, it just spreads across multiple pads, but can be re-cleaned and re-applied with flux

    I did another nforce 4 board after this, an old A8N-E, the chip was so stubbron, it would hardly move till I put the gun on high, and got it RIGHT UP to the damn chip. Smelled something burning, which is expected, then I realized the power clip connector next to the northbridge melted like cheeze, and I got laughed so hard, I still don't know why

    in the end, I realized I need a magnifier, I was doing this with my super perfect vision, but I could easily still miss a pad, which might nullify the whole thing

    I need a flux pen, not a syringe, and i'm starting to think about using an auyoe, but I don't have the $100 right now

    in addition, I used no protection for the rest of the board, and am thinking about doing the foil thing, still not sure what that spells for the pico caps on the top of the nf 6 chips

    any ideas? I want to eventually do this for hp dvs and other nvidia plagued products
    Cap Datasheet Depot: http://www.paullinebarger.net/DS/
    ^If you have datasheets not listed PM me

    #2
    Re: poor mans reballing

    Originally posted by Uranium-235 View Post
    in addition, I used no protection for the rest of the board, and am thinking about doing the foil thing, still not sure what that spells for the pico caps on the top of the nf 6 chips
    For my one and only heatgun reflow, I used aluminum foil to protect the areas around the nvidia chip. I also thought about using an aluminum pop can cut out in the shape of the nvidia chip?

    I have seen other people use kapton tape when using a hot air station to protect the surrounding components.

    http://www.ebay.com/sch/?_kw=kapton%20tape

    http://www.youtube.com/watch?v=ePp6YagHElc
    Last edited by retiredcaps; 01-20-2012, 03:14 AM.
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    Comment


      #3
      Re: poor mans reballing

      Reballing without using stencils and balls isn't reballing. What you are doing would be closer to reflowing but with a twist where by you are going to do nothing but make a mess. If by a stroke of luck and you did manage to get one to work doing this it will not last as long as a proper reflow would so why go through all the extra steps.

      Comment


        #4
        Re: poor mans reballing

        I would be inclined to agree, your chances of success are infinitely higher by just reflowing if you don't have the equipment to reball. Use a good flux, make sure you get hot enough to melt all the solder and keep it liquidous for a time. It is difficult to get it right using the proper equipment, you may get some to work for a while. Good luck

        Comment


          #5
          Re: poor mans reballing

          hm. well at least I can get it off (most of the time, might use foil to try). get it cleaned up. After that, it seems its just getting the balls, stencils, chip holder, and it shouldent be a problem

          maybe I should get an auyoe, but errg $100 is a lot of money next to the lack of money I have
          Cap Datasheet Depot: http://www.paullinebarger.net/DS/
          ^If you have datasheets not listed PM me

          Comment


            #6
            Re: poor mans reballing

            Yeah, You NEED stencils and proper balls if you want to do it properly and have a chance of it actually working. Soon as you go about just sticking dabs of solder on they end up different sizes, which is going to create a big problem when you solder it back onto the PCB.

            That's for starters. I don't think I'd be game enough to even try it with a heat gun. A proper IR BGA rework station is what you should use.
            "Tantalum for the brave, Solid Aluminium for the wise, Wet Electrolytic for the adventurous"
            -David VanHorn

            Comment


              #7
              Re: poor mans reballing

              you want to lend me 7 grand?

              I think in most cases, and air bga rework station (auyoe) would be ok, yeah a heat gun might be a problem
              Cap Datasheet Depot: http://www.paullinebarger.net/DS/
              ^If you have datasheets not listed PM me

              Comment


                #8
                Re: poor mans reballing

                I saw some little reballing "stations" on ebay that came with like 100 stencils, little hand held screen holder, and balls and flux for like 39 bucks and free shipping from china, I am going to order it and see how good it is, figure if it works once or twice it has paid for itself

                Comment


                  #9
                  Re: poor mans reballing

                  Got me thinking, I remember seeing a video on Youtube of someone using a heat gun in some kind of jig to remove a big BGA: http://www.youtube.com/watch?v=F3B83e0gp4Q

                  Doesn't show the setup in detail but it certainly looks like it works, he's got a thermocouple there but looks like just for readout and not controlling anything.

                  There may be some kind of grille etc inside that square pipe to reduce airflow and\or make the heating\airflow more uniform etc. No idea if it's necessary but I notice that some BGA nozzles sold for SMD Rework stations have a grille in them: http://www.ebay.com/itm/BGA-Nozzle-2...-/260913745008




                  Also, there's this: http://www.youtube.com/watch?v=ZrWRToFImbk (Stand which should work with majority of hot air rework stations)

                  But this one: http://www.youtube.com/watch?v=38IaWi7Y-Nw seems to use a hotplate for bottom heating\preheating. I have noticed the 'proper' BGA rework stations also have a bottom heater, so might be worth looking into. I think for anything this major you should probably do preheating etc.
                  Attached Files
                  "Tantalum for the brave, Solid Aluminium for the wise, Wet Electrolytic for the adventurous"
                  -David VanHorn

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