I BURNT UP our SOLAR - QFN Reflow in a Van Down by the River - Manly Man Skills

well as many of you know we're on a multi-month trip through Canada US and Mexico and this rig is mostly solar-powered and at the heart of this system is the S BMS 100 solar charge controller and while I really like this controller it does have one little flaw that's not really a flaw but user error and that is that you need to disable your breakers from the solar panel to the charge controller before powering it down if you disconnect the power from the controller while the solar inputs are switched on it will fry the main integrated circuit on the controller so unfortunately I've blown up our charge controller fortunately we did bring a spare unfortunately I've blown it up too so today we're going to show you how to reflow a 64 pin no lead quad flat part while living in your van down by the river [Music] so in an earlier life I worked in a facility that we had the proper reflow equipment to do this properly but out here camped in the desert you need to work with what you have so basically you're going to need something that's broken yours doesn't need to be specifically this broken thing but it needs to be broken you need some replacement parts and you need some tools so I'm not going to bombard you in the beginning with all the tools you're going to need but I will call out what I'm using and where I got it when appropriate as we go along here so as I've said before we're going to repair this solar charge controller this one's really slick because it has these flat-head Allen machine screws that hold it together so I'll take this apart real quick to show you so the screws are all out of the back now let me just show you how clever this is the whole controller is made up from stacked printed circuit boards so as I take these layers apart you can see these are a touch sensitive button but they're just traces that go to a row of contacts here that then transpose down to the next layer and these are just thick circuit boards oops this one is the display in the front here these are thick circuit boards that just stack together and even these here are a printed circuit board although there's no copper traces on those and that's it it all comes apart and this back layer is actually really slick it's an aluminum plate that he's designed with the traces that straight on the aluminum it's not on the aluminum but the traces are plated onto the aluminum plate for heat dissipation so I think this is a really clever design I just keep breaking it fully my faults but yeah I've learned my lesson twice so we're gonna get to fixing it so this is the main board that we're working on this has the display on a ribbon cable which is quite delicate we need to be careful with that and then this chip here is the main charge control I see and that's the part we need to replace so I've ordered the parts and some tools to be able to do this on the road these are are the charge controller chip I'll put the links to everything in the description if I forget to mention something I will call it okay so I ordered four of them I've also bought stock in the company so let me show you how small these are using my ESD safe gloves and work surface you get in here really tight on that so this is the part it's referred to as a 64 qfn which means it is 64 pins along the perimeter of the chip this is the bottom side we're looking at and qf n stands for quad flat no leads so there aren't even any leads to solder to there just little pads on the bottom of the chip okay so you're going to of course need some special tools and this is going to be tight and hard to show because it's a small thing and I have big hands but I ordered this little three hand clamp it's called a third hand commonly used for soldering wires when you have no skill you clamp one side of the wire and then give the two conductors touching and then you can solder it with a magnifying glass but I'm going to use it to hold this PCB so that I don't burn my table and you'll see why in a second and then that I brought along a c-clamp just a typical clamp and I'm going to set this up on the edge of my table just because this little stand is too light and flimsy and would fall over so you need access to the top and bottom of whatever board you're trying to reflow apart on so that's a big part of the reason why using this a clamp it'll all make sense in a moment but this is really inexpensive if I remember right it was about ten bucks or less so that's step one step two is you need to isolate these other fragile bits so this foil ribbon cable for the LCD screen is fairly temperature resistant but I just want it out of the way just for physical access to it so I'm going to use a little piece of Kapton tape here thanks to Eminem Overland for sharing that with me makes very good light color change filtered lens also and then this tape is neat stuff it's poly Olamide tape called Kapton is the 3m trade trade name for this product and it's heat resistant and will keep the hot air from getting at these other parts where we don't want them don't want it and even though they may still heat up it will prevent them from getting blown away or moved around by accident so cheap insurance just to keep everything hunky-dory there so I've isolated all the all the stuff I don't want to affect and I've got it square in the sight of the magnifying glass here so the next thing you're going to need obviously are some tweezers I got these from digi-key which is the electronic supplier I used in an earlier life same place I got the electronic components you get a pension that and you're going to need some solder I have ordered from digi-key as well chip quick SMD 29 1 ax it's a liquid solder where the the solder alloy is in paste form little tiny balls inside of a flux carrier so it has this cap take that cap off put this plastic needle dispenser on get yourself a little piece of something and it comes out there I'll show you close-up of that in a bit so the thing about solder is as it gets old it gets oxidized and doesn't doesn't reflow as nice as well as this is likely at lead-free solder and I prefer my solder super leaded so you can all hate on me in the comments later but it does flow at a lower temperature and it flows much nicer so for that reason I add new solder on top of all the old solder so that it reflows and the new flux helps the old solder just flow nicely so you'll see that here in a second this is the next tool you're going to need it's a very inexpensive hot-air gun it's this one's distributed by sparkfun electronics I recommend them highly it's 20 bucks or so and I got it on the same order from digi-key so it just runs off of 110 blows hot air out the business end and you'll see up close here so this is recording and it is the solder paste will heat up and then turn from this gray color to metallic [Applause] so we want to heat up the board gently and evenly no hot spots necessarily so I'm going to spend the first little bit just heating it gently and generally let's see it goes from a shiny grade to sort of a darker dull gray and then all of a sudden it's gonna start bubbling and blistering that's the flux melting and doing its thing and then it will go silver metallic color starting to get shiny like the Terminator and then when you see that it's flowing evenly all around that's how you know the solder has melted and we get in there with users and just left the old part out so I know if you heard me but once it goes silver metallic that's how you know the solder has melted and the flux has helped the old solder melt and you just get in there with your little tweezers and lift the old part out so next you need to remove the solder that's residual here on the PCB and for that I'm using just a regular pen soldering iron with a very blunt tip you can see there and this is solder braid or a quick braid and as you can see it's a woven copper wire like material and it's just used to soak up the solder and you don't want to linger on this too too long because the heat can cause that copper trace material to delaminate from the board from the printed circuit board below so just lightly and rather quickly you don't want to linger like I said get it all off like that till it's nice and smooth maybe do one more I don't want to say scour but you want to almost scrub just to release that if there's any shmoo on there get that off so then the next thing you need to do is use your french-canadian rubbing alcohol and a q-tip and that will help lift the solder flux there's a Joule flux from the PCB and clean off any fingerprint or oils or any other inorganic or organic oils and that looks pretty good so I forgot to mention this before I took it off but you want to verify that this marking the square in the top right corner of the square that little dot that indicates pin 1 and on the printed circuit board here you can see that little circle which is unique in that corner and that indicates pin 1 on the circuit board in this case I already knew and that they went there but before you take the old one off you just want to make sure that you have their part in the right place so be aware of that because it needs to be keyed or clocked in the right direction to work obviously and so if you were doing this properly in a proper facility you would have a stainless steel stencil with the holes cut out in the appropriate locations for the solder paste and you'd use a squeegee to squeeze it on there in this case you use a big old syringe and you dollop it on I don't have an answer or a recommendation for how much to put on and you'll see when I go to reflow this that it'll look like a big ol mess anyway so it doesn't really matter if you have a little too much and you need a little bit in the center for the ground plane so that big pad in the center is usually ground so that's that and then the magic bit to take your chip and very carefully put it approximately in the center approximately square she's a thing of beauty mind the windows were firing up the hot air gun again here and you want to keep this very flat so that's you know when the soldered reflows and melts it doesn't go skidding sliding down the side and and just give it the best chance to center itself and you'll see that when the solder melts that part will kind of shimmy and squirm right into place so I'll try and talk through it we'll see if you can hear me again you want to heat the whole board generally you don't want a thermally shocked one area so you'll see moving the generally heating everything until I see the solder paste kind of go from the shiny grade I could see it slide round those from this shiny gray sees liquid to sort of a dull crusty coral forests you can see that I'm able to affect its position just with the airflow so I'll just slowly let that heat up until it gets until the flux sort of flashes off a little bit and it gets a little harder yeah it's kind of moving a little less and this will take some time about a minute especially if you're using a small heat first as I this one is 300 watts on me so it's not ideal so as the flux melts and evaporates the pace becomes slightly thicker and as you can see I'm getting closer and closer here and it's not really affecting it in the same way it's not speeding off on me they eat it up and you see them your right side there the sod is melting I go to school left a little bit there we go you saw they're all refilling and melting don't pull out just because you think it's done give it a few seconds extra just to get the heats distributed evenly underneath on the ground plane everywhere else should be good and then there are reflow [Applause] schedules I guess who gets felon for the temperature it should follow but I'm just going to slowly let it fuel or allow it to that is keep it slightly warmer for a moment's longer here solidified slower and there we have it looks like a disaster right you can see all these solder blobs here and here and here and here and here and it's a big mess but if you're not everything is gonna be okay so as you can see I've got these little shorts there so we're gonna use the regular ol Weller pen tip but instead of using this blunt Orenda stip I ordered say again from digi-key this replacement optional tip looks now it has a bent tip but you can see here much finer tip okay so this tip is up to temperature now I'm just applying a little bit of solder to the tip just to coat it with nice fresh solder so that it doesn't have oxidization and other Ghibli's on there wipe it off and keep in mind that this will oxidize quickly because it's hot here's my and then I'm going to just use this tip and take it off bad bad word usage there every time I touched the pads a little bit of that slaughter is going to come and jump up onto this tip so you can see there I got rid of that one short and then I'm just getting it off of the the soldering tip by touching it to that same solder braid so don't know if you guys can see that there and so as I touch it to the copper braid there just wicks into that I've got about six of these shorts here so now using some more rubbing alcohol cleaning away any flux residue from the solder paste should be very little because it is a low flux rather a low residue solder paste it actually says no clean required but when you hit it with this soldering tip there it does kind of scorch and leave it a little black so next is to inspect your work and I can't even see very well the quality of work I've done so I actually use my phone and take some pictures so I'll do that and overlay that here this phone has an amazing camera when i zoom right in take a picture of each side so there you can see between pin four and five the tiniest little whisker joining them so actually not ten five but the fifth pin on that side so I do have the one really bad one actually maybe two I'll touch up again with the soldering tip and then I'll show you the next step okay so I've gone through with the fine point soldering tip and verified that none of the pins are touching although they do look like soldered hand soldered parts because our pins rather because I soldered them with the soldering iron so they don't have that smooth glossy look like they should for reflow part so I'm just going to reflow the solder again and that will make them all nice and bulbous and beautiful looking okay so I've just finished just reheating everything till the solder got all glossy and silver looking again and then let it at its own rate and I'm just going to splice in video from my phone which is actually an amazing way to magnify this stuff and as you can see in this clip the solder joints are all bulbous II and silver you know not touching each other and so the next test the next step is to test it so I'll show you how to do that next so the next thing you're going to need is a multimeter with a continuity test that's basically will beep if there's any metal connecting between the two parts you're testing now obviously these pins are going to going to be far too large rather the test probes are going to be far too large to touch each of those pins but fortunately you can visibly see the trace here so arrange this for this camera here you can see that that first pin on the left goes here to this side of this resistor and the second one goes to this side of this resistor and it's not making any contact there then you go from the that side of that resistor to the third or actually the second and third are shared they're sweet low to the fourth no contact there and so on and so on I'm just going to work my way all around the chip following these traces to these complementary parts and verify that no two are touching now I already know that some are touching for example this here is ground I believe for another station so you can't see that on the close-up camera back here I'm touching the USB Jack jacket and I know that this is ground so I have the advantage of knowing which pins are ground because this solar controller is open source and he's shared the schematic for it as well as you can look up the datasheet for the part you're replacing and some pins may be connected internally or you know the datasheet specifies this needs to be ground and this also needs to be grounded this needs to be ground which is very common on a a high pin count part like this so you can just use that as a reference and just verify that if pins are shorting that's probably why so I'll go through these systematically off-camera one by one from pin to pin making sure that there's no shorts as well as the ground we know that that big pin on the back is ground so I'll hold the the one probe on the USB jackets there and there the shield rather and go through each of these pins you can even just wipe gently wipe the side of the part and that pin I know should be ground and the one next to it but the other is not and there's one more over here so go through all these make sure the adjacent pins that shouldn't be touching aren't and ones that are connected to ground are and then the next step put it all back together power it up and hopefully everything works okay so I've gone through every every adjacent pin and through the ground plane nothing's reading to ground nothing's shorting to any of the pins so it should be good now we just need to put it back together time to test it out okay this is honestly honestly the first time I've powered this up after changing the part out so I need to have the battery management lead on there to start and then I'm using a big battery bank I've got a ton 1818 650 s ammo box as my spare power source for whatever and some jumper clips will go from ground here to the ground lead here sort of and then from positive here to battery positive here with a blocking your view communication error [Music] Randy minutes lay down I've got this lead wired to the battery negative and this is a battery positive test clip that test lead on there you can see it's being it's able to read the RAM and the EEPROM and the ISL 94 203 is working so success so there you have it I've actually fixed both of these already I was lucky the first time had no problems with any shorts I went together just fine the second one I just shot the video for today put it all together and it didn't work I had to take it apart reflow some of the pins to get them to make proper contact but 20 minutes later I just filmed this it boots up and works properly so it's not impossible don't be afraid to try it this equipment which I'll link below is super cheap the hot air gun was about 20 dollars and the the solder paste is inexpensive that is probably the hardest part that you could solder in a home gamer environment I'm you know a 64 128 pin quad flat-pack like that so it's not impossible don't be afraid to do it the worst-case scenario is it will still be broken when you're done thanks so much for watching we'll see you next time

Channel: Everlanders

Views: 17,951

Keywords: vanlife, QFN, TQFN, Reflow, DIY, SMD Repair, SMD, Hot Air Solder, Vanlife, RVlife, everlanders, diy truck box camper, android auto, diy camper, baja california sur mexico, baja california sur road trip, diy camper shell for truck, diy campervan conversion, raspberry pi projects, hot air soldering gun, hot air soldering diy, hot air soldering iron, hot air soldering station, hot air soldering tutorial, hot air soldering, hot air soldering station diy, smd repair tools, smd repair kit

Id: 7RdbXw5mJsA

Length: 27min 3sec (1623 seconds)

Published: Tue Mar 12 2019