Dell power jack refuses to budge
in [Hardware]
|
Prev: McAfee Virtual Technician
Next: periodic dust cleaning
From: 123Jim on 16 Mar 2010 05:09 Hi all, I was trying to replace a power jack on an inspiron 1501 laptop. An operation I have avoided for some time due to the possible outcome being the catastrophic destruction of the motherboard or components thereof. I removed the motherboard , but could not melt the solder sufficiently to release the power jack. I used two different 30 watt soldering irons with sharp and not so sharp iron points and one 100 watt soldering gun. My technique leaves a lot to be desired: place motherboard on newspaper, place finger under motherboard next to jack, apply iron to one joint at a time so that it melts the solder and pushes through. unfortunately there being 8 joints and stubborn solder made it impossible to move. The best way would be to heat all eight joints simultaneously, but I have no idea how to achieve that. what I need is a nice soldering guide, specifically for computer parts. any ideas? cheers
From: GT on 16 Mar 2010 05:35 "123Jim" <jnkjnjnini(a)uhnuhnunuhnuy.invalid> wrote in message news:hnnht7$f95$1(a)news.eternal-september.org... > Hi all, > I was trying to replace a power jack on an inspiron 1501 laptop. An > operation I have avoided for some time due to the possible outcome being > the catastrophic destruction of the motherboard or components thereof. > > I removed the motherboard , but could not melt the solder sufficiently to > release the power jack. I used two different 30 watt soldering irons with > sharp and not so sharp iron points and one 100 watt soldering gun. > > My technique leaves a lot to be desired: place motherboard on newspaper, > place finger under motherboard next to jack, apply iron to one joint at a > time so that it melts the solder and pushes through. unfortunately there > being 8 joints and stubborn solder made it impossible to move. The best > way would be to heat all eight joints simultaneously, but I have no idea > how to achieve that. > > what I need is a nice soldering guide, specifically for computer parts. What you need is one of those devices that suck solder away once it has melted, then you can go round as many legs as you need to. Don't know what they are called, but have seen them in Maplins (UK).
From: Paul on 16 Mar 2010 08:41 123Jim wrote: > Hi all, > I was trying to replace a power jack on an inspiron 1501 laptop. An > operation I have avoided for some time due to the possible outcome being the > catastrophic destruction of the motherboard or components thereof. > > I removed the motherboard , but could not melt the solder sufficiently to > release the power jack. I used two different 30 watt soldering irons with > sharp and not so sharp iron points and one 100 watt soldering gun. > > My technique leaves a lot to be desired: place motherboard on newspaper, > place finger under motherboard next to jack, apply iron to one joint at a > time so that it melts the solder and pushes through. unfortunately there > being 8 joints and stubborn solder made it impossible to move. The best way > would be to heat all eight joints simultaneously, but I have no idea how to > achieve that. > > what I need is a nice soldering guide, specifically for computer parts. > > any ideas? > cheers > > These have a teflon tip, which is why they can take the heat. The unit must be cleaned occasionally, to remove accumulated solder. These are pretty cheap. http://en.wikipedia.org/wiki/Desoldering_pump You can also get a desoldering station, which consists of a vacuum pump, leading to the tool head, which has a source of heat, plus a soldering tip with the connection to the vacuum pump. That too has to be cleaned frequently, as the glass tube inside the tool head, clogs up with solder after a few joints have been freed of solder. A filter in the vacuum path, prevents stuff from going down into the pump. This is a more expensive solution, and not a casual purchase. http://www.howardelectronics.com/jbc/images/LDIS-2A.jpg This is another solution, but this is suited more to cosmetic cleanup, after most of the fun is over. I use the thin stuff, like 0.050" wide or so. I find the really wide solder wick to be too hard to get hot enough. One trick to using this, is I compress the wick by rubbing a smooth tool tip over the wick. The squashed wick sometimes picks up a bit better. (You won't find the thin stuff at Radio Shack. I have a solitary good electronics store in town, and that is the only place I could expect to find the good stuff. Radio Shack is more like to have the fat useless wicking braid.) http://en.wikipedia.org/wiki/Solder_wick One other poster here, a few years back, suggested ChipQuik. It is a low temperature solder. The idea is, you add some of that low temperature solder to each solder joint. Then, if you can apply moderate heat to all the joints at the same time, you can get all the solder molten. After the device has been physically removed, you can clean up the lands carefully with solder wick. (An issue here, is the metallurgy. The purpose of removing all the solder on the component surfaces, is so when you use new solder, the consistency is appropriate for the situation. You don't just plunk the new chip down and seat it in the low temperature solder. I don't know what the long term reliability implications would be for such a soldering job, if you didn't clean up after using it.) http://www.chipquik.com/instructions.html When working on PCBs, you probably already know that some have poor adhesion properties. On the PCBs at work, we had excellent physical durability (one of our blank PCBs, cost as much to make for just the PCB, as does a fully populated Chinese computer motherboard). I could leave a soldering iron tip on one of our boards all day long, and not lift a pad off. I've worked on a couple retail computer boards, and have lifted two pads so far. The finish steps and materials used in the board constructions, affect the durability and ability to do repairs. If you see a small rectangular pad, all by its lonesome on the surface of the PCB, that is the kind of thing that will "wipe" off the surface of the board, if you apply pressure with the soldering iron tip. It is a tricky balance between not using enough heat, and bolstering your efforts by pressing on the work with the tip of the iron, versus using too much heat, and simply frying the pad off the surface of the board. It is one of the reasons they make soldering iron stations with a temperature control knob and temperature readout, so you have some idea what temp things are at. In the picture here, you can see a Weller station, complete with well worn sponge for cleaning the tip of the iron. A good unit has an easy to use dial on the front, for adjusting the set point of the tip. I don't have one of these for home use, but these were common at work. http://w3.externet.hu/~gylab/weller/weller2.jpg In this example, you can see how to remove a large quad flat pack. With a hot air rework station, plus a ton of expensive custom tools with just the right dimensions for the various chip outlines, you can uniformly heat up a chip until the solder is molten on all the pins. The thing in the middle of the chip, is there to pull upwards on the chip to free it from the board. This is the kind of thing, where "practice makes perfect", and usually one person on staff has "recycled" enough chips from boards to get good at it. I limited my activities to soldering irons :-) http://upload.wikimedia.org/wikipedia/commons/5/5b/Desoldering_with_hot_air.jpg It is even possible to handle chips on the bench, where the contacts are hidden underneath the chip. Those chips are ball grid array. Materials used at the factory, for a lot of soldering jobs, take the form of "solder paste", which is screen printed onto the surface of the PCB. That is part of the trick to getting the solder to stick well. Soldering of big components will probably involve a "profile", a defined temperature ramp for "preheat", a period of time for "hold" at the peak selected temperature, followed by a controlled cool down ramp. The trick to quality work here, is X-ray inspection after the job is finished. While the defect rate is low (one bad joint in 100000 balls), it still pays to X-ray, to see if there are any voids or cracks or the like. Some computer chips can have 1500 balls on the bottom, and doing a good job of soldering those is not trivial. http://en.wikipedia.org/wiki/Ball_grid_array Here, you can see a manufacturer recommending how to solder a component. This kind of information is mainly for encouraging good technique at the factory. It is harder to get this kind of control on your typical rework bench (if you have a limited budget). http://www.triquint.com/prodserv/tech_info/soldering.cfm The typical budget allows for the temperature controlled solder station (with the ratty looking sponge on it, which you're supposed to keep wet), a desoldering hand pump, a few rolls of wick, and a lot of cursing and swearing. Keep a "swear jar" near the bench :-) Have fun, Paul
From: 123Jim on 16 Mar 2010 08:49 "GT" <ContactGT_rem_ove_(a)hotmail.com> wrote in message news:4b9f50c2$0$14947$c3e8da3(a)news.astraweb.com... > "123Jim" <jnkjnjnini(a)uhnuhnunuhnuy.invalid> wrote in message > news:hnnht7$f95$1(a)news.eternal-september.org... >> Hi all, >> I was trying to replace a power jack on an inspiron 1501 laptop. An >> operation I have avoided for some time due to the possible outcome being >> the catastrophic destruction of the motherboard or components thereof. >> >> I removed the motherboard , but could not melt the solder sufficiently >> to release the power jack. I used two different 30 watt soldering irons >> with sharp and not so sharp iron points and one 100 watt soldering gun. >> >> My technique leaves a lot to be desired: place motherboard on newspaper, >> place finger under motherboard next to jack, apply iron to one joint at a >> time so that it melts the solder and pushes through. unfortunately there >> being 8 joints and stubborn solder made it impossible to move. The best >> way would be to heat all eight joints simultaneously, but I have no idea >> how to achieve that. >> >> what I need is a nice soldering guide, specifically for computer parts. > > What you need is one of those devices that suck solder away once it has > melted, then you can go round as many legs as you need to. Don't know what > they are called, but have seen them in Maplins (UK). I have two of those devices but haven't figured out how to apply this sucker device before the solder solidifies. You'd need three hands! and the reflexes of a cat. ;) .. Another suggestion I read somewhere was to use a wick. Copper I think. The idea I think is to heat the solder, apply some copper wire to it, and it might be attracted to the copper and remove it's molten self from the joint. but I never reached the point where solder of any quantity in my Dell jack made it to the liquid state. I began to think it was no ordinary solder but solder that would only be liquid above any heat I could apply. I have now re-assembled the laptop after much brutal treatment of the motherboard (slipped screw drivers, some flexing of the board, extended heating of the jack, many expletives) ... Now the cable fits much better in the jack. (previously it was loose) ... I don't think it is going to reliably charge the battery, on current observations , but it might now supply power while the cable stays connected ... All very unsatisfactory .. but I won't try again to replace a jack until I have studied, and read up on soldering techniques. Even then I will have no confidence that it will not end in disaster.
From: 123Jim on 16 Mar 2010 09:33
"Paul" <nospam(a)needed.com> wrote in message news:hnnua9$3q5$1(a)news.eternal-september.org... > 123Jim wrote: >> Hi all, >> I was trying to replace a power jack on an inspiron 1501 laptop. An >> operation I have avoided for some time due to the possible outcome being >> the catastrophic destruction of the motherboard or components thereof. >> >> I removed the motherboard , but could not melt the solder sufficiently >> to release the power jack. I used two different 30 watt soldering irons >> with sharp and not so sharp iron points and one 100 watt soldering gun. >> >> My technique leaves a lot to be desired: place motherboard on newspaper, >> place finger under motherboard next to jack, apply iron to one joint at a >> time so that it melts the solder and pushes through. unfortunately there >> being 8 joints and stubborn solder made it impossible to move. The best >> way would be to heat all eight joints simultaneously, but I have no idea >> how to achieve that. >> >> what I need is a nice soldering guide, specifically for computer parts. >> >> any ideas? >> cheers > > These have a teflon tip, which is why they can take the heat. > The unit must be cleaned occasionally, to remove accumulated solder. > These are pretty cheap. > > http://en.wikipedia.org/wiki/Desoldering_pump > > You can also get a desoldering station, which consists of a vacuum pump, > leading to the tool head, which has a source of heat, plus a soldering tip > with the connection to the vacuum pump. That too has to be cleaned > frequently, > as the glass tube inside the tool head, clogs up with solder after a few > joints have been freed of solder. A filter in the vacuum path, prevents > stuff > from going down into the pump. This is a more expensive solution, and not > a casual purchase. > > http://www.howardelectronics.com/jbc/images/LDIS-2A.jpg > > This is another solution, but this is suited more to cosmetic cleanup, > after most of the fun is over. I use the thin stuff, like 0.050" wide > or so. I find the really wide solder wick to be too hard to get hot > enough. One trick to using this, is I compress the wick by rubbing > a smooth tool tip over the wick. The squashed wick sometimes picks up > a bit better. (You won't find the thin stuff at Radio Shack. I have > a solitary good electronics store in town, and that is the only place > I could expect to find the good stuff. Radio Shack is more like to > have the fat useless wicking braid.) > > http://en.wikipedia.org/wiki/Solder_wick > > One other poster here, a few years back, suggested ChipQuik. It is a low > temperature solder. The idea is, you add some of that low temperature > solder to each solder joint. Then, if you can apply moderate heat to > all the joints at the same time, you can get all the solder molten. > After the device has been physically removed, you can clean up the > lands carefully with solder wick. (An issue here, is the metallurgy. > The purpose of removing all the solder on the component surfaces, is > so when you use new solder, the consistency is appropriate for the > situation. You don't just plunk the new chip down and seat it in the low > temperature solder. I don't know what the long term reliability > implications would be for such a soldering job, if you didn't clean up > after using it.) > > http://www.chipquik.com/instructions.html > > When working on PCBs, you probably already know that some have poor > adhesion properties. On the PCBs at work, we had excellent physical > durability (one of our blank PCBs, cost as much to make for just > the PCB, as does a fully populated Chinese computer motherboard). > I could leave a soldering iron tip on one of our boards all day long, > and not lift a pad off. I've worked on a couple retail computer > boards, and have lifted two pads so far. The finish steps and materials > used in the board constructions, affect the durability and ability to > do repairs. If you see a small rectangular pad, all by its lonesome on > the surface of the PCB, that is the kind of thing that will "wipe" off > the surface of the board, if you apply pressure with the soldering > iron tip. It is a tricky balance between not using enough heat, and > bolstering your efforts by pressing on the work with the tip of the iron, > versus using too much heat, and simply frying the pad off the surface > of the board. It is one of the reasons they make soldering iron stations > with a temperature control knob and temperature readout, so you have > some idea what temp things are at. > > In the picture here, you can see a Weller station, complete with > well worn sponge for cleaning the tip of the iron. A good unit has > an easy to use dial on the front, for adjusting the set point of the > tip. I don't have one of these for home use, but these were common > at work. > > http://w3.externet.hu/~gylab/weller/weller2.jpg > > In this example, you can see how to remove a large quad flat pack. > With a hot air rework station, plus a ton of expensive custom tools > with just the right dimensions for the various chip outlines, you can > uniformly heat up a chip until the solder is molten on all the pins. > The thing in the middle of the chip, is there to pull upwards on the chip > to free it from the board. This is the kind of thing, where "practice > makes perfect", and usually one person on staff has "recycled" enough > chips from boards to get good at it. I limited my activities to > soldering irons :-) > > http://upload.wikimedia.org/wikipedia/commons/5/5b/Desoldering_with_hot_air.jpg > > It is even possible to handle chips on the bench, where the contacts > are hidden underneath the chip. Those chips are ball grid array. > Materials used at the factory, for a lot of soldering jobs, take > the form of "solder paste", which is screen printed onto the surface > of the PCB. That is part of the trick to getting the solder > to stick well. Soldering of big components will probably involve > a "profile", a defined temperature ramp for "preheat", a period > of time for "hold" at the peak selected temperature, followed > by a controlled cool down ramp. The trick to quality work here, > is X-ray inspection after the job is finished. While the defect rate > is low (one bad joint in 100000 balls), it still pays to X-ray, to > see if there are any voids or cracks or the like. Some computer chips > can have 1500 balls on the bottom, and doing a good job of soldering > those is not trivial. > > http://en.wikipedia.org/wiki/Ball_grid_array > > Here, you can see a manufacturer recommending how to solder a component. > This kind of information is mainly for encouraging good technique > at the factory. It is harder to get this kind of control on your > typical rework bench (if you have a limited budget). > > http://www.triquint.com/prodserv/tech_info/soldering.cfm > > The typical budget allows for the temperature controlled solder station > (with the ratty looking sponge on it, which you're supposed to keep wet), > a desoldering hand pump, a few rolls of wick, and a lot of cursing and > swearing. Keep a "swear jar" near the bench :-) > > Have fun, > Paul Great stuff... I also found this; http://www.aaroncake.net/electronics/desolder.htm I should have used a solder pump or a wick on the miniscule amount of solder I managed to melt .. at least I think I did.. If I had added ordinary solder to the joints I was heating .. would that have allowed the heat to melt the target joint? .. I tried that briefly, but the solder just bounced past the target joint . and threatened to make a mess .. so I only tried it once and gave up. The laugh is I have some things I would like to try again .. but I won't be disassembling this laptop again until it is officially dead for a second time. :) |