Identifying power cycling, repairing Macbook logic board

https://www.youtube.com/watch?v=UcFkOX4PJHM

hey everybody we're gonna try to do a  daily board repair video again so this here is an a 1502 retina MacBook Pro that has no power we're gonna try to  figure out why it has no power so let's   open it up   dig into this machine and see if we can make it work again and as you can see here it's taking 79 milli amps and also we don't get a green light so one thing you should know from my last video is  that the no green light could be a   number of things it could be pp3 before too short it's a ground it could be PP 3 before to missing it could be the power button is stuck so I'm because if the power button is stuck pressed down its gonna think it's trying to do an SMC reset so I just unplug the keyboard because the keyboard is going to be  responsible for the power button as you can see we have no change here so I'm  going to take the board out of the case and we're gonna see what happens there so let's get the board out of this case and go from there but while we're taking the board out of the case just don't  remember that we should have definitely send in the clowns where are the clowns please send in the clowns and we're gonna plug this in again now that everything has been unplugged we're  gonna see if that makes any difference doesn't seem to make a damn bit of  difference so we're gonna open up a   schematic for the eight to zero - for nine to four and Paul Daniels is  lovely software available at PL Daniel's   comm that's PL Daniel's comm there's an   open-source version that you can try that does not include the thing where you'll automatically find signals in the PDF that you right-click on and the board you and vice versa but it's still really good stuff and you should check out his site because he's contributed a  bunch of lovely stuff to our industry like the multimeter software that allows you to see the voltage on screen right over there it's good stuff picked at  random indeed picked at random first thing we're going to do is check PP 3 V 4 to  underscore G 3 hot what do we do here when the Chargers not working if we take a look we have 18 volts and ground and adapter sense adapter sends is going to  be what allows the machine to tell that a charge is attached and it's going to  also talk to the charger and tell the charger hey you can turn on now I'm  attached Thank You Paul Daniels adapter sense is going to be where the SMC speaks to the charger says hi I am a  Macbook you can turn on now I'm a   Macbook I want my 18 volts so it's going to speak to it over here and as you can see there's a chip this is X on one side and ends on the other side now where it  says end on the other side this is going to be where the signal goes to the computer on sis 1 wire and if we take a  look we look for sis 1 wire that goes to   which ship called the SMC that goes to a   chip called the SMC right here it's a so   the system management controller is   going to be what speaks to the charger but it goes through a chip over here first and in order for that chip that it  goes through to work it needs to be   getting power now if we check out that chip over here this chip that it needs to go through is powered on its VCC pin and the power from there comes from this chip a logic gate which will send 3.42 volts over here if smc bc AC ok is present but this logic gate gets his power from pp3 v4 to  underscore g3 Haan so let's see if PP 3v for to underscore g3 hot is present on this MacBook Thank You Sonya for agreeing with my method of  anger management so it says that pp 3 v4   - on this board can be found I believe somewhere around here there we go  BP 3 before to underscore g3 hot so   let's see what we get we're gonna turn on Paul Daniels is lovely happy multimeter software which Paul Daniels was so gracious as to donate to the stream and we are going to see what we  get and we get 1 point 1 4 volts 1 point 1 4 volts is not what we're expecting we  need 3.42 volts so the first thing we're   gonna do as per that instruction manual that I link to down below a guide on  board repair the first thing that we're   gonna do is see if we have a short circuit to ground there's many reasons a  power rail cannot be present then I go   over them in that documents and one of   them is a short circuit so let's see if   a short circuit to ground is what we   have I've changed the multimeter over here to resistance mode one probe on  ground the other on output but you have two point eight ohms to ground two point eight ohms to ground means that the power is going straight to ground rather than going to where it's supposed to be  going to so we are going to see what it   is that's getting hot using what we like to call here the please bro camera so  here we have the please bro camera anyway so we're gonna go to display capture over here put the chats on the side so I can see what's relevant and let's see what's getting hot now the please bro camera has what's called the please bro button one sec let me just copy over my power supply transform so  that this all looks proper now as you can see the ISL is getting warm but up  here the pp 3 4 2 circuit is also getting very warm Yeah right there that's hot that's  peepee bus g3 hot so let's see is it   this seems like it  looks like we may have a bad peepee 3v4 to regulator chip so let's go back to  the schematic in the board view and see what that thing is if we go back to the schematic and the board view and then we  go right over here you'll see that that chip that we're having problems with it  looks like the pp3 before to regulator itself this chip is a very simple job with this chip does is it takes the charger voltage which is going to be PP  18 V 5 or battery voltage P P bus g3 ha   12 point 5 volts or 18 point 5 volts and it turns it to 3.42 volts on output now this chip is 15 degrees hotter than the rest of the board which tells me that perhaps it has failed and it is most likely what is causing my short circuit to ground so I'm going to disconnect the please bro machine I'm gonna say thank you please bro machine because the please bro machine helped me please bro rather than have to use my brain to  solve that problem I was able to use the please bro machine to solve that problem so now we're going to take that chip and we are going to replace it with another one you know it doesn't look bad if you take a look over here that doesn't look like a messed up chip at all but it is  most likely what is causing my problem now do you guys understand why it is  that I went for the PP 3 before to Ralf first because I saw that there was no  green light and green light requires PP   3 before 2 so I put a small amount of   flux there did you get parsall from Amazon I have a bunch of parcels from Amazon at my apartment that I have to  bring upstairs I got uh I got a cat litter box a bunch of cat food I have to  open and check all the little things because usually weekly for the AMAs I'll  thank everybody who sent something and also at work I have greenies if any of  those of you thank you so much by the way okay so now I've removed the chip now the first thing I want to do is see if  that was actually the cause of my   problem all along since it was getting warm I just want to confirm before replace it so I'm going to measure to  see if I have a short to ground on pp3 before 2 and I actually still do have a  short 2 grams on PP 3 before - so the regulator was getting hot because it was pumping too much voltage into it but that was not my actual problem all along so I did something stupid I went off to  the thing that was getting hot rather than going after what was actually causing it to get hot that was dumb and that's something that I usually know better at but you know it's been a while so I've been I haven't been doing as  much of the slightly more business administration type of stuff so that has been screwing with my skill set and turning you back into an idiot so what I  need to do here is I need to not be lazy and actually inject 3 point 4 volts into the system and see what actually gets hot and go from there so I'm going to  inject 3 point 4 volts into the system right now and add PP 3 V 4 - using my  power supply let's just change the voltage that the power supply puts out because sending 18 volts into that power line will make the board very sad so I  put the ground to ground and now I'm   going to put the 3 point 42 volts directly on the pp 3 V 4 to  okay now we turn the outfit on and it's   using one amp so whatever's getting warm should be fairly obvious so I'm going to  put the please bro camera back on the screen here so you can all look at the please bro camera now as you can see here the ISL 6259 chip is 87 Celsius now before I thought that the ISL was just getting one because I had a charger plugged in this chip was getting warm and because it was short-circuited so the pp3 before two chip was getting warm it was actually getting about warmer than this because it was supplying this with power and it was shorted rather than address the actual problem I addressed the symptom of the problem and that was dumb that was a  dumb thing for me to do it's something I   usually tell all of you not to do figure out the root cause of the problem and address that rather than simply dealing with the symptoms and I would have figured that out quicker had I actually injected power I was being lazy the machine was only taking 70 ml amps it  wasn't putting out enough power to   really tell if there was a short I   figured maybe I'll get lucky and something will get hot and something did get hot but - - things got hot at the same time and one would have gotten much hotter than the other if I had actually injected voltage which I didn't do  because I was being a lazy ass and I   should probably upload this just so that you understand why it's important to not be a lazy ass and how being a lazy ass can trick you so we are going to remove my wire it's no longer needed we're  gonna replace the ISL six two five nine with a better one if you want to know where to find an ISO sixty five nine you can find them in store dot rossmann group comm okay so this is our ISL 65:9 chip and also check this out look there's evidence look at that bubbling over there see this by the way if you want to check out get a microscope at the similar quality to  mine you may notice that the image quality on this thing is absolutely amazing compared to a lot of the people who do this it's because this microscope allows me to get perfect focus on the trinocular port this can be had at store dot Rossman group com we are selling microscopes the chip didn't really want to come off of the board which is actually something that I'm used to when it comes to chips that die they have a tendency to weld themselves to the board and I was expecting that to be a nasty or under it  than it actually was so now I'm going to   replace that lead-free solder with some leaded solder and after that I'm gonna it's gonna make it easier for me to wick that leaded solder off of the board solder solder you so let's get an ISL 65:9 put on here and also a new PP three before to regulator put on there [Music]"  [Music]" this does not work as well as the other tips that I was using I don't know how Camille was dealing with that he was Camille managed to find a way to use a tweezer hot tweezers tip on the micro setting pencil and I don't  get it   also I'm pretty sure that resistor goes somewhere but I'm not quite sure to what that resistor is too small to be in any part of this board here okay now we're gonna replace these two chips these are chips that you could buy on store it out rossman group comm I  they suggest you buy them now before the prices go up do the lovely tariffs you get an iso six two five nine down here you can see I tend all those pads we put a proper amount of flux there I'm tending all little circles around the ISL 6259 because I like little tin circles makes me happy don't make fun of  me I like my toon circles someone said thank you for all the effort you put into your videos I have been a PC tech for ten years there's no way I could ever demonstrate what I do live like you can I hope you consider writing a book sometime in the future would be the Sun zero of MacBook well a book is not exactly the medium that I would do best at that's why I do everything in video but thank you very very much I really appreciate that thank you seriously thank you so we are going to  take this chick over here the regulator that was actually a totally fine chip we're gonna put it over there onto the other board these are both chips that can be purchased at store dot Rossman group com you should probably get one of them now before we get a one or two or three hundred percent tariff but on the rate that we're going now what did USPS say Lois oh this is the best part of it so  you know in that USPS video that I did a   few days ago where I said that there's   this really kind lovely amazing post woman that really puts a lot of hard work and effort in and she does a  perfect job remember when I said that and I was speaking so well of that post woman and I said anytime that she takes a day off for vacation that's when things go to and nobody shows up or  the person who shows up doesn't scan stuff well guess what happened so at the post office she came by today and apparently I don't know if it's her supervisor the very dude that didn't  pick up any of my packages properly or   scan them and other people are actually blaming her they're blaming her for the fact that a complaint was filed the one that actually did their job properly every day the one that in the video that I cited in my USPS postal complaint did a good job that's the one that they're  good that's the one they're throwing under the bus so they're doing it  doesn't seem like anything good as   getting done there but I don't think it's the post office I don't expect anything my packages have not moved at  all most of those customers at this point have gotten and another one send a  lot of the people who've complained we   just sent them another one I don't have time to wait so  and neither did the customers at that but such as life so we are going to go  back here and go around that ship like so get rid of all those little excess solder balls that came out and then plug it in plug it in plug it in  like Glade I thought it was really really really lame but they're they're  blaming the person that I actually said did a good job rather than blaming the person that I have on camera doing a bad job like the person that I have on  camera not doing their job is the one that's not in trouble the one that's in  trouble is the one that I made two to   three months ends up in that video and said was a great employee let's see what we get now so we have replaced the shorted ship another one the PIPA there is l6 two five nine responsible for our pp bus g3 hot we're  gonna plug it in it's not turning on   because I still have the power supply sets a three point 4 volts rather than 18 so we're gonna change that this is  going to be set to eighteen point five volts on on okay as you can see we have a green light but it's only taking 20 milliamps so PP  3 V 4 2 has likely been restored so if I   were to measure PP 3 V 4 to the first power rail that was missing I would bet that I've got it  and I do now pp bus G 3 hot over here this is the AIA by the is l6 two five nine we're getting 12 volts that's not what I would normally expect 12 volts we're supposed to be getting 12 point 56 for only getting 12 okay now we got to  figure out why that's bouncing back and forth like that see the amperage twenty three thirty six twenty three thirty six twenty two twenty three twenty six it's  going back and forth so that's strange so let's take a look around that is l6  two five nine area because something funny is going on here since those are you getting twelve point fifty six not that you know let's just check some of  the current sensing circuit current sensing is measuring just fine is charged a dcn present painting in vaults pp buses still 12.0 eight that's a funny number let's see if pp5 es5 is present TP 5vs5 goes to five volts and then three one zero five volts three one zero okay so  we've got a short-circuit on some other rail and we got to find it and what do  you know check it out so I noticed that it was power cycling but I mean my power cycling is that we were looking at the amperage the machine was taking it was going from 23 million 237 back and forth back and forth back and forth that's why it's very important of a power supply but you that I use rather than just using a normal charger I want to see how much amperage is taking I want to see what it's doing I want to know what it's  doing and just by plugging it in that doesn't tell me what it's doing static voltages don't give me the full story so  now what I did right now is I decided to   check another set of power rails in the computer that come next so let's just bring those up in the schematic and the board view over here using paul daniels is lovely beautiful amazing software so  if we go down here there's gonna be a   list of different power rails check this out so it says always present rails so I  check PP but g3 hot that was present then I decided to start checking the s5  rails has five rails and machines at him beyond when the machine is off so PP  5vs5 PP 5vs5 was jumping up and down so then I  decided let me check PP 5 es 3 another and PP 5 es 3 that's gonna be a rail that supposed to be present while the machine is hibernating just to give you an idea G 3 hot always on as five those are gonna be the rails that are supposed to be on the machines off as three the rail OS for the rails that are on when it's hibernating s three the rails on  when it's sleeping as oh the rails that are on when the machine is actually on  and being used so for instance s three the machine is sleeping the RAM gets power but the screen doesn't so RAM would be an s3 rail s oh that is a rail that's on the computers and use CPU v  core or LCD backlight those RS o rails now I checked the s3 rail over here and that one of that first s3 rail I just happen to get lucky it's shorted to  ground zero ohms to ground on PP 5 e s3   which is what I was checking on pin 2 of   that chip over there I just happen to   know that it's there because I've checked it a million times already so let's take a look and see if  there's a hardy point on the board where I can inject five volts in there so this board didn't just have one short this board likely has multiple shorts and we  are going to attack and make humble every single last one of those short circuits so let's see where I can solder a wire to to inject 5 volt into the board and then we're going to go up  slowly from there it looks like on this capacitor over here I can do that right over there so on this campus campus a  campus sitter over here we are going to   inject fire well we can inject up to 5 volts but I want to start with 1 and see what gets warm so let me go back to my  power supply software and lower that to   1 volt yeah we do have the cursor officer I probably broke something by  being a Paul you can code this software as well as you like you're  never gonna be able to stop me from being an idiot or a fool so you should stop trying many have tried before you and failed all right so let's just what things on let me just turn you off at  the time being all right we're gonna turn this on wow it actually lowers itself 2.71 volts and takes the full 5 amps so at 0.7 volts we're taking a straight-up 5 amps right here it's almost as if I sure it's  almost as if I just connected this directly to ground itself that's  insanity Sean Hannity so let's take the please bro camera and see what the heck it is that could be taking all of this power on this board so we're going to  turn on the please Braille camera the please Braille camera is what's gonna tell us when something's getting warm and let's see what it is that it's  taking 5 amps at point 66 volts so it   looks like this transistor here is   getting a bit warm but let's see what hat what's looking like on the other side of the board yeah this area on the other side of the board is just blank so  the only thing I've really got to go on   here is this transistor so let's see what that transistor over there is for shall we now if I open up the schematic and the board view cue 7520 well what do  you know this the transistor responsible for creating this power line imagine that look this here is our u 75 but this is our TPS 509 eight zero this is  responsible for creating PP 5 vs 3 and the transistor that's going to be doing the switching and the pulsing is broken so the way this works the way that we're  going to get from 12 volts to 5 volts with the switching power supply is  simple so if I want to take your 12 volts of the battery over to 5 volts the way I do that is by sending pulses of 5 volts through I mean pulses of 12 volts through so here I'm going to send 12 volts then 0 then 12 volts then 0 now since this is less than half that means that I'm going to want to send this much 12 volts this much 0 this much 12 volts this much 0 this much 12 volts this much zero so I'm sending pulses and what's going to happen over here if you is that this chip is going to control and just make this full screen and make it easier for all of you who are watching there at home this chip is going to control this transistor this transistor Scot this over here PP VIN s 5h s whatever the hell of it that's P P bus g3 hot that is  going to be the twelve point six volt rail twelve point six volts goes into the transistor the chip tells the transistor open BAM its inch twelve volts through the coil 2 PP 5 es 3 and then it closes and ensign 0 volts through then it opens and sends 12 volts through and then it closes and send zero volts through now that that coil is  going to do is it's not going to allow it to switch very quickly it's not good the coil is gonna make things slower it's not going to send 12 0 12 0 it's  just gonna wind up setting instead of   doing 12 0 12 0 12 0 it's gonna go 5 5 so before the coil you've got 12 0 12 0 12 0 12 0 and after the coil you've got 5 it's gonna get averaged out through that section over here where you've got a coil going to the output and then a  bunch of capacitors to ground that's   gonna be used for smoothing and also storing some power so that transistor is  shorted to ground so now let's take a   look at what it looks like under the microscope because it may be telling as  to what's going on here I'm also gonna stop sending 5 volts to this machine because that's torturing the poor little thing my chart my power supply is  screaming in pain right now and that is   the transistor that is our transistor over there okay now we're gonna take a transistor off of the donor and put it on this this is my donor to the right notice that the Trent that this transistor never left my hand now I  always have the board that I'm working on under the microscope and the board that I'm not working on away from it  because the board that I am stealing the part from I don't really care if I knock something off right next to it that's  not what matters to me what matters to   me is not losing my component not losing my place so something that I noticed with a lot of newbies is that what they do is they'll have the component the board that they're stealing the component from in the microscope and then they'll they'll take it off and then they'll go oh crap well how am I  supposed to get this back onto the new board so they put it down and then they take the new board and they put it under the microscope and by then the little component that they put down it's just gone just poof vanished bye-bye and that's not a good thing so I usually have the component the board that I'm  stealing a component from next to it   now we're going to turn the power supply back to 18 volts we're going to plug it in  see what this thing can do as you can see it's taking 640 milliamps and the fan is spinning the fan is spinning because the power rails now work and the machine is fixed so as I have this is  interesting so I had a short circuit on   pp3 before to that chip is getting hot when in reality the ISL 65:9 had died and the ISL 6259 after fixing that and pbht three hot being restored in PB  three before to being restored we then had a second short circuit on PB 5 es 3 and the way we were able to tell that there was an issue there was I saw a  power cycling when I say power cycling I   mean that my power supply was saying that the board was taking 23 male amps then 37 and was going back and forth in  a steady fashion 23:37 23:37 23:37 so I decided to start checking out the other rails pp5 es5 was going back and forth back and forth back and forth now what a newbie would have done at that point they would have started trying to troubleshoot pp5 es 5 which is not what you do PP 5 es 5 is  jumping up and down because of another rail so one of the things to recognize here is that the chip that creates PP 5 es 5 right over here u7 501 which is  available on stored rossmann group.com this chip over here is not just responsible with BP 5 es 5 it's also responsible PP 3 B 3 s 5 and PP 5 es 3 now this one ship is providing three different rails so let's unload me let me try to make an analogy here so if I'm  at the gym and I am lifting weights let's say I'm doing benchpress and the person right next to me is doing squats and he hurts himself if he hurts himself doing squats that doesn't stop me from being able to do my benchpress however if I'm doing benchpress and somebody takes a knife and stabs me in  the quadricep even though the quadricep is not the set of muscles used for benchpress I'm good I'm good that bars gonna fall on me because you just stabbed me in my quad the same thing is  true here whereby even though PP 5 es 5 is a totally separate rail from PP 5 es  3 PP 5 es 3 is not created from PP 5 es   5 these rails nothing to do with one another in terms of sharing a specific power line they both are made by the same chip so  since they're both made by the same chip I'm not necessarily gonna see oh is this cap shorted to ground is there a short here what I'm not gonna replace at cps 509 zero anything that hurts this chip is going to hurt any of the rails it  creates so if there's a little transistor that's hurting my TPS five one nine eight zero this chip is gonna go out short to ground turn off turn off turn off now if the if this transistor is shorted and trying to take five amps out of this thing it's gonna go ah turn off turn off now this chip unfortunately it's kind of dumb you know it's it's  this chip cost a few dollars it's not a    genius by any stretch of the imagination so it's kind of dumb so it's  not only going to turn off this rail over here that's shorted it's also going to turn off this rail over here that's  not shorted so PP 5vs5 jumping up and down was actually a red herring for the fact that PP v es 3 was the rail that had been stabbed in the quadricep and the chip dropped the bar on itself because some somebody stabbed it in its PB v es 3 now after fixing that the board now functions the fan spins and if  the fan spins let's face it the rest of   the board probably works no need to do   any other test and they're pretty sure it's ready to go right back to customer I'm kind of kidding but anyway that's it  for today and as always I hope you learned something and again I'm gonna try and put as much effort as I can into doing these videos every single day I  want to have a new upload for you every single day we're gonna do our best to  make that happen I want this to be a   consistently educational channel I got a   note from somebody recently and and I   got an email from somebody that actually said that they were on welfare and they are now working at a repair company doing this very work here because they were watching the videos and they learned something and stories like that are the tight getting that type of  feedback or seeing pictures of the repair shop that people start that's the type of stuff that actually motivates me  even if I'm really tired and I have a   lot of work to do to come back here and do as much as I can to teach these boys these to teach what it is I'm doing and to also walk you through every step so  that it's easy to understand stuff again emails like that like I could get a thousand bad comments a day and like one person that sends something like that is the stuff that makes all of this worth it and I'm going to really try to  keep paying it forward and releasing stuff like this this educational because it's it's just there's no feeling like getting like getting emails like that so  that's it for today and as always I hope you learned something excellent data recovery not the best camera what happened Steve what do you think is  gonna happen if you're sitting there it's a meter run through it you push }