This video shows the diagnosis and repair of a mid-2013 Macbook Air computer with an 820-3437-B motherboard.
This particular machine has some issues with its PPBUS_G3Hot power rail – it should be 8.6v and it’s actually measuring just over 1v.
Here we take a look at the schematic, board view and find the problem, replace the faulty component and get the machine back up and running once more.
Unfortunately I cannot share these documents or link you to them but a search on Google will return them without too much aggravation. Any part of these documents used within this video are intended to facilitate the repair of the faulty equipment shown and for no further purpose.
Many thanks for watching and please remember to comment, rate and subscribe for more videos.
I hope to have more Macbook videos up on a regular basis going forwards – fingers crossed as I do enjoy working on them.
right hello ladies and gentlemen and welcome to today's video and today we are having a slightly different change of flavour and we are going to be looking at this MacBook Air now this particular MacBook Air is an a 1466 it is covered in this nice little plastic blue protective case as they say 1466 with an eight to zero 3437 beam on the board of it now by my calculations I believe that puts it in around the mid 2013 category and this particular map what comes to us with no power so if we open the lid and I believe the battery is charged and we try to power it on you'll notice we get absolutely nothing no lights no backlight no screen no nothing at all if we plug our charger in then we should see I'll just kill the light there then just bring you down for a moment you should see that we do indeed have an orange light on our charger but again we have absolutely no power at all so I'm just going to put you back in the dry pot for now so please do bear with me today boys and girls because I'm working on my new environment for the first time so things have been jerry-rigged up a little bit not quite going with power sockets where I am so it's a bit of a mess but what can you do so hopefully within a couple of weeks we'll be cooking on gas in here but for now anyway so as I said this MacBook Air we have an orange light on the charger but our power is completely dead so we are going to walk into seeing what we can do with this now this particular MacBook Air has a back story don't they all and essentially this was brought to me by my mate who is an electronics repair guy himself but he doesn't do this old insider stuff anymore in fact he has a friend where this actually came from and my friend's friend has an electronics repair shop specializing in laptops and computers however it doesn't do component-level stuff he only he only does like past swapping and things like he's not a component level guy so essentially what happened is he had a customer walk into a shop and apparently this had some water damage at some point but it's been working fine however the customers saw I noticed an issue with Wi-Fi so he went to go look at the Wi-Fi thinking in Europe you know thinking he knew what he was pop the Wi-Fi card out but he didn't notice that the machine was left on it was actually in standby and apparently at some point either somebody called his phone or somebody walked into the shop whilst he was actually removing the Wi-Fi card he turned his back for five minutes came back and put the thing back together and of course it's dead as a doornail so he specs so he said to my mate that he thought the Wi-Fi antenna may have touched something shortly out you know so he was doing work in the Wi-Fi region of the board and that's all we've said so I think I might know what this is and those of you who do a little bit of work on these machines probably screaming at screen right now what you think it is as well but we'll go over it and we'll show you the process and how we come to the conclusion that we do so as you can see dead as a doornail orange light on the charge now why is the orange light on the charger significant well I'm going to show you something now so if we just have a quick look at the computer screen now for a minute the computer screen view I am going to show you the schematic diagram for this motherboard now this is one particular reason why I actually quite liked working on Apple products is because you can find the schematics now unfortunately these are not distributed by Apple you by any means at all so what Arthur eyes de pairs so you know this document has found its way into my hands by Google unfortunately because of that I cannot possibly tell you where you can get these from all I can say is if you spend five minutes on Google you too will find them but unfortunately I can't tell you where you can get them from now I do believe at some point in this document in fact yeah I can see there on the front there is a clue as to where you can't find these diagrams so unfortunately if you ask me if you message me or comment below where can I find them fortunately I liberty to tell you all I'll say is use Google you will find it without too much surgeon and the same goes for the board view so what's the difference between a schematic and abhorred view well aboard view is a logically laid out map of the motherboard so the components appear where they are on a schematic diagram it's a very logically laid out so the layout on the paper isn't necessarily the same layout on the board so you need the board view to find the components and the schematics to tell you what those components are between the two you've got a very good chance of navigating yourself successfully around the board and you know being able to pinpoint the issue and everything else so that's really quite nice so yes this is a schematic for this diagonally and out for this motherboard so it's Nate 2-0 34 30 MB yes it is indeed and you see the doc document there dated September 2013 so it isn't mid 2013 model it sees a Core i5 so we're just going to remove the power supply for that matter book now because that's useless I am going to strip it down now I'm going to take the motherboard out and we will go through what we need to do to get this thing working again so pair with me in a second boys and girls and we'll get this board out and I'll join you a sec okay so what we're going to do is we are going to take a look and see what's going on with our map so in order to do that we actually have this board out now and we're going to just connect the charger now just to verify what happens so we connect the charger we can see we have a green light and that turns to orange we get absolutely no activity on the fan but we do have a light on our charger now the light on our charger is fairly significant because the lights on the charger is controlled by a circuit called the one wire circuit and the one wire circuit actually utilizes a components on our motherboard and I see on our motherboard to actually control the charging and everything else that the board does so he's basically a power management IC and if that's working then we must have some activity on our board it must be working to some degree so we can't get the thing to start and it appears dead but there's obviously some sort of activity there so what we're going to do is we are going to do what most people should do in these circumstances and we're going to check the power males and the main power rails on a Macbook are something called g3 hot males and if you basically think of AGT hot males as an oak tree for example right okay and you've got the big you know the big tree trunk in the middle and then you've got the bigger branches running off and then you've got all the little smaller tributary branches on the leaves or and essentially the g3 hot males are the big trunk that's what everything runs off and g3 hot males are some like the main power males that supply all the other little components elsewhere in the system with your sort of power if you like and if one of those is missing if one of those big branches is missing then essentially all the little branches and the leaves connected to it and also missing so if we've got a power rail missing then we could have lots of things missing on our board which means it doesn't power well so in order to do that how the hell do you find your way around it no what you do if you have a look in the schematic you can find a section called power males now most people put these on my front page one by known Apple not Apple they put them right towards the battery somewhere so I'm just going to have a quick flick through this PDF and then I will list somewhere here we go so power aliases here we go so what page you're on page 62 yeah page 62 of 76 seems a logically enough place to put everything well that doesn't so as we can see here these g3 hot always-present males so these are the rails that should always be running no matter what the system is doing so essentially you've usually got three states of power S 5 s 3 and s 0 and if you think of those as a pyramid so s 5 is when the computer is off so what sort of things do you need when the computers off how about you know the charging circuit the charging controller RC power management things like that because of course it's still desirable to charge your laptop whilst it's not being used in s3 for example that's when the computers sleeping so you don't need the graphics chips and you don't need the screen and things like that but you do need memory and things like that because of course everything you're working on needs to be stored in memory so that when you open the lid and actually we see were works the computer knows where you weren't can carry on from where you left off s0 is everything that is in use when the computers running so that is usually absolutely everything that you can think of but underlying you know the foundation to those vales is the g3 heart you know the basic main always-on power rails and the thing is is you can't get to the next state without having everything from the snake previously so you can't get to an s3 state without having everything from s5 you can't have everything in s0 without having everything from s3 because usually the s3 rails will gain power from s5 and use that to convert to other s3 males and so on so forth first 0 and of course if you don't have the always-on always present GT hot rails you can't have anything so that's essentially what we've got here and we've ended up where a lot of our board is actually not working properly so if we have a look at this power aliases sheet here and we can see that page 62 of this 76 page document the first power rail that's actually listed there is pp boss GT hot and the machine actually uses PP + g3 Hart to generate a very very lot of the power males they actually use could be considered the main power male you know within within the back book and if we're missing that then we are going to have a big problem so what we need to do is we need to check and see just what that's voltage should be whether it's present and if it is present if it's actually doing what it should do and if it's getting to the right places that we need to get to so that's what we're going to go and do now so if we have a look at this g3 Hotmail here then on the machine on the on the screen so just going to zoom into it and you can see here the PP boss g3 Hart comes in and the voltage there is eight point six volts so where we fangy people must really heart we should find a voltage relative eight point six volts if we don't then we've got a problem there and obviously we're going to need to find out what that problem is so let's jump to the top of this document and see if we can find where pp was GT hot is generated so this is sort like the first step of troubleshooting if I chop if a problem is he a great if not then we've got a bit of a hunt went on so let's find P P boss g3 huh I should be in on the scanner – I'll bloody hell on a cart type okay so we see it here on the left-hand side so that's where it's being an input for something so it's already generated at that point so we're not interested in that's for Thunderball anyway hi since current you know high side current sensing again that's not of interest to us that's an input and g3 hot power supply three point four two that's not really of interest to either but this actually is so here we go so this is where it's actually generated if we take a look here q as we can see it's actually an output from this line here and it's going to system so this is where people's GT height is actually generated and this is of interest to us so this actually comes from this is L this into cell is L 6 2 5 9 qf m package and this is denoted as u 7100 on the boulevard so on the schematic diagram that is what we refer to the il-62 v 9 has it's basically a charging power management IC and what it does is it takes voltage essentially our buddy hang on I hate Adobe either because please zoom is off right so essentially what it does is it takes power from up here so this is from like the charger and things like that when the charge DC in PPD cm and the battery which is further down that's on the right and essentially it brings into this IC so what it does is is it converts the 16 or 18 volts from the charger and converts it down to that eight point six months that we need to run the system so in order to do that what it does is it uses this Q 71 30 here which is a dual N channel MOSFET package and essentially a MOSFET is a fancy switch so what it does is it switches on and off on and off on and off and off very very quickly and it sort of gives it spikes so you get some you know 16 volts 0 16 volts 0 16 volts Azir and the number of times and the length of time it spends at zero actually averages out that voltage to a lower voltage so what it does is it does that so it switches on and off and it gives you those those spikes those are all collected in this inductor here l71 30 which smooths everything else and coming out there you get a nice smooth voltage through that fuse there f71 40 and out to the system goes 8.6 volts at PP must really hot at least that's the theory so because people use g3 Hartley's our first rail going on a check we need to make sure that we are actually getting people got GT hot so we are going to measure that at F 71 40 so this is usually where it shows up so how the hell do you know where F 7140 is well this is where open board view comes in quite useful so open board view has our board view schematic on here so essentially what this is is a road map of all the various bits and pieces in the connection point of our board as it's actually laid out in front of us so we can actually find things really rather easily and it's open source and it's really nice so we're going to open the a20 I think if I'll take 7b board and revision that we've got and that's it now so it's opened in the same layout as we have on the board in front of us on the table so that's always nice and what we're going to do is we're going to do a ctrl F and we're going to find F 7140 because f 7140 is where we can measure and see my PP gostrey that comes from so if we just zoom out a little bit there we can see that it's a fuse and it's a fuse right underneath L 71 39 main board here L 71 30.2 remember where everything smoothes out that's here and a fuse F 7140 is here and F 71 40 pin number two is where everything shows up so we're just gonna have a look under the microscope and see what looks like so bear with me a moment try and get this in in focus flying so I this is our inductor here this is L 71 30 + f 70 140 is just behind it f 71 40s there and it does look a little bit brown on top a little bit so what we're going to do is we're going to connect our charger to our DC and board and we're just going to see and we're going to measure what L 7140 gives us on pin 2 so that's our 7140 I'm just going to show you the multimeter in the other window bear with me a sec I'll try and get everything sort of in order all right so F 7140 is that little white fuse there so if we have a look on the schematic it says that F 7140 is an 8 amp 24 volt fuse it's a 12-hour six package so what we're going to do is we're going to put a 1 lead on ground I'm going to put meat in two volts DC we're going to put our black probe on ground and we're going to put our red probe on the left-hand side up into our that fuse there and we're going to get a reading of point 99.1 so it's just over one volt maybe steadily going so that should be eight point six volts and it is so on the other side of that fuse pin one we can see we have our eight point five nine volts so we also know that of course coming out of L 71 39 inductor we should see eight point six volts eight point five nine eight point six volts on eight point five eight so it's coming through the inductively fine let's get into the charger side of the fuse absolutely fine but the system side of the fuse is Bullard and I don't know if you'll be able to see you this actually I'll try and get your view I'm just going to disconnect the charger again it's absolutely pointless not me in that you might not be able to see this they might get a horrible mess but you can see there look down the side there's a nice burn mark down the side of L 7140 well f 70 140 and so we're going to change that component so I'm going to get some hot air on it so gonna get some flux just gonna move the old microscope out the right I'm getting back in the main view let's get that compound and swapped out so hopefully then well it may not be our only problem but it's certainly going to be one that isn't going to help us so we're going to get that few swapped out now then these things always look a hell of a lot bigger than they do on the camera than they actually do in real life I mean one of the big inspirations for my channel is a guy called Lewis Ross mone works out in New York doing a lot of this Macbook repair stuff and I'll tell you what I've watched so many of these videos and you you see things on this microscope cams anything and you know doesn't look too bad compared to a PlayStation PlayStation bits look huge compared to some of these it's amazing how small some of the shite is all right I'm gonna have to go and unplug a few bits and pieces and move stuff about because I'm going to plug sockets so of course we remembered to remove power from the board before we touch it so I would have liked to have done this under the microscope camera for you but I'm going to plug sockets and obviously the ring light on the microscope camera is an easy one to get rid of what we're dealing with a big viewers like this one try not to block too much of your view with this okay so that's f71 fault you've gotten rid of so now we need a nice new ones are put in its place okay I plugged up more flux on that hot air back okay so I'm just going to flow that into position Oh okay so as a pain trying to do that when you're trying to look down the viewfinder of a camera let's try not to block anybody's view there you go so our old fuse is looking decidedly sorry for itself so we get rid of that okay so that's that done so what I'm gonna do now is I'm gonna get rid of a fema extraction because the noise does my bloody head in when we don't need it okay and then I'm just gonna go and change the plugs over again so we'll put the charger back in I'm gonna see what we get so are we going to get anything how are we gonna get nothing at all so let's zoom you back in okay let's get rid of the multimeter the multimeter for now ah okay let's bring you back let's bring this morning in view okay so we've got found that so let's see what happens when we hit this charger now judge connected fan is spinning got a green light a nice top we've got an orange light here we go so yeah these airs do sometimes do a weird thing where they start stop start stop start stop and then start yeah Karl totally weirded out now why but we can see there the fans running and there is a bit of an in-joke on this as far as MacBooks go that when the fan spins we're done which costs a lot of our bollocks may be amazed how many people actually do believe that once that fan spins that's it my fixed so they don't believe in Boonton open – OS X to make sure it doesn't kernel panic because something else is wrong you know a lot of places will call it fixed but can't get into our sects but they'll put windows on it and of course it'll boot and then we go you know well must be something else wrong with that now if you just do your job drop like you'd be okay so what we're going to do is we're just going to assemble that board now and we're going to put it back into the chassis and we'll boot it and hopefully I'll get working back so bear with me boys and girls well just go put that back in the chassis and we'll see what we get right okay so we've got this thing back together and time for the big switch on so I'm just going to connect the charger like or something automatically powers up we have an Apple logo and my up course this thing has a nice SSD inside it so that's it we are done and this is all working again so we can unde it back and we can save a few bushes from my mates mate but yeah so that's that one so as always if you do have any questions or you found this useful then just drop us some comments I'm a message or something like that it's always much appreciated if you like what we do on this channel and hopefully we'll have a few more Apple stuff to come then by all means you know hit that subscribe button I say if you found it useful alike and everything is always much appreciated – as is if you did find this useful and it helped you out in any way if you do so have a couple of minutes there just to let the end dad play through it always helps what we do on this channel and as always boys and girls I will see you on the next one so for me it's Tata for now so we know we don't have a short to ground there so let's just see what we read across that resistor we're getting nothing at all so oh well they're open line basically means it's infinite resistance so no no connection at all between the two points no resistance no anything we flip our probes around and again there's absolutely nothing there either so it would appear that we have a problem with this resistor