A1278 Macbook taking 200 mA but not turning on

all right today we're gonna be working on yet another MacBook this MacBook over here has a Bitcoin sticker on it this MacBook has a Bitcoin sticker I imagine he did not sell one was worth $19,000 a Bitcoin because this is an h1 78 and they're getting it fixed in 2019 let's take a look inside this MacBook and see what's going on with it here we have an 8 to 0 dash 2936 MacBook this is a 2011 MacBook Pro that this a 2-0 2936 is out of the machine we are going to plug it into the charger and see what it does now this is taking 200 milliamps and not turning on typically in a 2-0 2936 should be taking five to seven hundred milliamps when turning on it's going to take 20 to 30 milliamps when p.m. sleep s4l is missing it's going to take a hundred 250 milliamps when every rail is turning on besides CPU vcore because all says power good is missing 200 milliamps typically means a short circuit to ground on PP bus g3 hot let's see if that's the case on this 8 to 0 29:36 so I am going to open up a schematic and a board view so we're gonna go through our power rails in this machine and see what's going on power rails on the older Prix 2013 machines are going to be on page 7 on this power aliases page we get a light on the charger and since we have a light on the charger most likely PP 3 V 4 2 is present and I do not have to waste my time measuring it so what I'm gonna do is I'm gonna check my PP bus PP bus appears to be 0 volts on this macbook 0 volts here actually nevermind I didn't have my multimeter on ground my bad bro 12 point 6 volts but not turning on ok so next up we're going to check some of the other rails here let's take a look at PPV RTC now you may wonder Louis you just skipped over a whole bunch of rails what's up with that well PP 3 V 4 2 is the rail that's required in order to power the SMC and the chips around smc that allow us to talk to the charger so I have a green light in my charger the green light my charger means that the SMC chip which is powered by PP 54 - is working and if that is working to some extent that means that this rail is working which means I don't have to check it now I didn't check pp DC it this is the DC impound if this is if I have a light that means that P P 3 V 4 2 is present if PP 3 before 2 is present then obviously the voltage coming from the DC n board is present so for instance let's say I'm having an issue where one device in my office like my microscope camera doesn't work I'm not going to bother checking the voltage at my breaker box if one item doesn't work because if my breaker box were broken if one then everything else that was on this circuit would also be off like my monitor and my lighting but since all that stuff is on I know the breaker box is good so I'm not going to go that far up the chain this is simply a sub rail of pp bus g3 hot just gotta check your because it's never missing unless somebody purposely removed a resistor connecting to there's a current sense resistor connecting these two that is almost impossible to corrode and the only way that's missing is if some jackass removed it which doesn't look like a case on this board next up we're going to go for PPV RTC underscore g3 hot this rail is going to be there I'm gonna tell you how I know this rail is going to be there later on but first things first we're going to see if it's present on this board and also I'm going to use this as an opportunity to just brag about my new toy lens this is a $500 lens and it does a lot of zooming and it is sexy isn't it I know I don't even have to use the microscope sometimes if I don't want to because I have this lovely LEDs now pp 3 V 3 4 PP v RTC g3 hot is present now how do I know that was present before I even measured it great question when I decide that I'm going to plug the power supply in and healthy and figure out what the amperage of the board is what amperage the board is drawing before I start what I'm doing is I'm ruling out a set of problems now P P bust g3 hot being short it's a ground or a higher level rail being shorted to ground is typically the cause of a two hundred mill amp amp amperage draw from this machine when I'm missing PPV RTC on g3 hot I'm also going to be missing p.m. sleep s4l and everything else and that it typically means a 20 to 30 mil hem draw my power supply here says that at 18 volts I'm drawing 2200 milliamps which means that that's most likely not the case this is why it's really important to make measurements for every one of these boards that you work on so that you could become more efficient over time every time you solve a specific problem on the board you're going to write down here is what I did here was the problem here is the amount of amperage uu is taking when I started and eventually if you're good at pattern recognition or have a half-decent memory you those ought to start automatically clicking to the point where you plug it in and the moment you plug it in and you look at that and you just take a look at the board and make a few one or two measurements you know what's going on with it and you can even get good enough at it if you really write down everything and you dig into what it is you're doing you can get good enough at the pattern recognition to the point where you just look at the power supply and half of the time you know what's wrong with that particular model board it's going to save you time and in this business saving time means making more money retaining your sanity and having happier customers and having happier customers is a great thing now we're gonna take a look and see what other where else may be missing so let's scroll up a little bit over here and let's check pp5 es5 i'll do that in the microscope this time i will stop being lazy and pp5 es5 can be found right over here 5 volts ok next rail we're going to check for PP 5 vs 3 PP 5 es 3 is going to show up on these capacitors over here let's see what we have on the capacitor okay when we try to measure the capacitor it looks like we have zero volts on that line now I have a PowerPoint presentation that I aggravated in libra office so I guess Libre Office presentation but PowerPoint sounds cooler Microsoft is really good at branding that's why I think they do well with stuff Linux has a terminal Microsoft has PowerShell it's like it's fits for the you know the Alex Jones's of the world PowerShell PowerPoint or anyway I had a PowerPoint presentation that gives you an idea of how it is you troubleshoot certain issues on certain rails I mean a certain issues in machine repairing using data and logic love it doing myself everyday in the automotive world awesome Jay I hope you enjoy the detective work that's what makes the job fun so what I have here is a document that's gonna show you how it is you find the power rails that are missing and all this kind of good stuff and how you troubleshoot and learn how to do this the way I do and it's a beginner's guide that is in my links down below and I will show you it on screen here for just a moment just a moment just one moment BAM and one and on the power rails page I tell you how it is that you should go about figuring out why a power rail is missing so if a power rails missing a couple of things are possible the first is that it's not being told to turn on so here I have my uh my microphone this is from my transmitter moment because you are not able to hear me for that moment because I told my smartphone to not turn on it wasn't an issue of power it wasn't an issue of a broken mic transmitter it was an issue of I was not telling it to turn on you also have no power issues so even if it is being told to turn on it be a short circuit to ground so let's see which of these is going to be true for this model board so the first thing we're going to do is figure out where PP 5 vs 3 is created so let's see how it is we would go about finding out where PP 5 es 3 is created so I'm going to right click on that bring out my board view and I'm gonna keep clicking on PP 5 es 3 until I find a page that looks like the page that's responsible for making it many of my students in the past had lots of problems telling the difference between where power was going in to something and when it was coming out of something so for instance here is my microscope camera I have power going into it here so this is where the voltage is going into my camera but this is not where the voltage is created the voltage from my camera is created at that wall Ward power adapter something that looks like this that is under my desk so this is where the power is being created and then this is going to be plugged into something where it's going into that so let's just plug this back in and I'm going to show you the difference between those two things since it happens to really confuse a lot of people that I've had here for training so if we click PP 5 es 3 I'm going to show you some examples and we're gonna go over how it is you can tell those things apart this is pp 5 es 3 but this is pp 5 es 3 going into a transistor PP 5 es 3 is pulling up a signal with this 100 kilo ohm resistor PP 5 es 3 is pulling up memory set isil LS 5 v l PP 5 es 3 in this scenario is not being created here that's not that's not what we're looking for so we're just gonna click again here PP 5 es 3 is going into the webcam connector to power the camera and the automated light sensor that's what ALS stands for here over here we have PP 5 vs 3 going into the hard drive connector so that is not it that's where it's gonna be powering the hard drive here that's the optical disc drive power here we have PP 5 vs 3 going into ahem into a USB power chip so this is what's going to power the USB items that you plug into the machine cpp fabulous leaders going into that so that's not what we're looking we're just gonna keep scrolling through this until we find out where it's being created same thing is true here this is it going into the chip that powers that little infrared remote that Apple II used to use in the front of the machines not it this is it going into a sleep circuit we want to figure out where what chip PP 5 vs 3 comes out of what creates it this is it going into an audio supply into an audio chip into an audio chip into another audio chip of some sort I imagine and we just continue and this is if going into a FET that's then going to be creating another rail PP 5 ESO so let's continue scrolling so here PP 5 es 3 is coming out of a chip called TPS 5 on 1 2 5 so let's find TPS 5 1 2 5 now shall we alright TPS 5 or 1 to 5 just gonna be used 7200 you're right hmm so here PP 5 es 3 look I found it PP v es 3 now this is coming out of here so this is about converter this chip is telling those 2 transistors went to switch and they're gonna turn the 12 volts that are coming in to them via pp bus as 5 into 5 volts out of it and it's over here 5 volt 3.3 volt power supply so let's take a look at where people how this is created and what's going to tell it to turn on now if you take a look and trip 1 is most likely going to be what turns on this chip so if we were to select TPS 5 1 2 five what I'm looking for is an enable pin here we go end trip connect to resistor from this pin to ground set threshold first set short to ground to shut down a switcher channel okay so a lot of chips what they do is they have what's called an enable pin so you send voltage to the enable pin and then it turns itself on similar to how turning a light switch depends the light switch on sending three volts the enable pin will turn it on and trip pins are typically the opposite of enable pins and enabled in a device with an enable pin is going to be off unless you tell it to turn on a device with an end trip pin is going to be on unless you tell it to turn off that's the difference so with this device the way it works is you have to turn it off it's going to automatically be on all the time so let's see how it is they managed to do that in this schematic so if we take a look n trip for Pete Val rail that's missing so this over here gets tied to ground through this transistor so this chip is always going to have its enable there it's always going to be wanting to turn on but this transistor over here is going to short that to ground to shut down the switcher channel when this signal is present so this here is an N channel MOSFET the way an N channel MOSFET works and you can figure this out from reading my document if you are at all intimidated by this we go over how this works and this document is 110% free it's not like I got a paid version of it that features all the you got a you know for the real version all of this stuff is really like kindergarten level stupid and it's does it's designed so that even somebody like me may be able to learn something from it now back to the PDF over here this is an N channel MOSFET which means that when the voltage on the gate G is higher than the source s then this will allow the voltage the flow from drain to source or source to drain and over here our source is ground which means that any voltage on the gate anything at all is going to allow this to open and it's then going to send our switcher channel to ground and it won't work so if P 5 vs 3 enable L is present it will turn this transistor on which will stop this from working that why it says underscore L by the way P 5 vs 3 the name of the power rail underscore en enable it underscore L when this signal is low so this signal over here enable this power line enabled P 5 es 3 is going to be asserted when the signal is low because when this is high this transistor is going to open and or type 2 closes the corrector you get the send power through and then it's going to go to ground and then the entropy shut down so the first thing I'm interested in doing here is checking out the entropy are you actually being told to turn on I'm also interested in checking out P 5 es 3 en l so let's see where that is going to be on the board we're gonna take a look and see where that is on our board so if we take a look at Q 7 2 2 1 over here at Q 7 2 2 1 you are going to have the P 5 vs 3e n L now I think that that rail is actually present and shorted to ground I think that based on our amperage usage and before I even measure this I'm going to tell you that that enable signal is likely going to be present the reason I'm saying that is because rather it's taking 200 milliamps rather than 20 it takes 20 to 40 milliamps when the signals are not present and it's not trying to make those rels it takes 2 to 400 milliamps when the signals are present and it is making those rails or is trying to make those rails but it's being shorted to ground again one of the ways that you get much faster at this and much more efficient especially if you're working on the same device over and over again are the same small set of devices is every time you figure out what your problem is whether you it's to your one or two of your three our troubleshooting process you write down all the symptoms the device showed you document that you don't plug it into a regular MagSafe you plug it into something you can measure the amperage and you check you and remember your measurements on different power lines or different rails and then you can then associate those with specific problems so I'm going to make the guess that this signal over here is actually already present on this board we're just going to double check and see and Lois your trousers are unzipped you may show more than you expect on crotch cam maybe that's by design and as you can see we have three point five volts which means that this is being in wait a second no that's not being enabled because that's a bit only enabled when it's low ah okay Lois may have been wrong here so P 5 es 3 en el p 5 that means if this is high this is purposely going to be sending P 5 vs 3 enable L to ground and that is that's no good so let's try and figure out what's going on here and let's also see if that's steady or if that's pulsing I may be right after all okay interesting it's going back and forth and it's pulsing now one of the reasons it could be pulsing is because there is a short circuit to ground it could be detecting there's a short circuit to ground and then turning the chip off to protect itself let's see if that's what's going on we're going so we here we're gonna measure to see if we have a short to ground on the output where pp5 es 3 is so I'm gonna go over here to where these capacitors are were it's don't work and we're gonna see what the resistance to ground is 11 Ohm's Mike you can't see that hey now you can get 25 ohms 31 ohms 39 ohms 50 hmm interesting we had something similar to a short but it appears to be going away the short circuit appears to be curing itself imagine that much interesting Wow the self fixing board yeah we're up to six kilohms at this point you know I'm gonna do something that's a little experimental here since I don't see much in terms of obvious damage I am going to remove that transistor that is gonna keep this chip from turning on and see if my rail is created so if you look at the schematic and board view you'll see that like I said that the end trip signal has to be high if it is sent to ground it will shut down the switcher channel and q7 two to one is what's responsible for shutting down the sensor chap the switcher channel so I'm gonna remove that chip and see if that has any effect on our rail being made what I'm looking to do here is see if there's an issue the chip or with the NA or the stuff that's making the enable circuitry is this stuff that's making the enable circuitry turning off because it sees that there's a bad chip or is there something else to it entirely there's only one way to find out we're going to take this chip off and move it to the side where the chip will be sitting sideways so we've disabled its ability to tell itself to shut down for the system to regulate it shutting down and it is capable of making 5 volts at that point so the the circuitry itself is do is good this chip is good the transistors are good all of that is good what we need to do is figure out why the system is telling it to do that that's where the fun comes in so this is very strange because at this point we have no reason for for 200 mill amp amp drop there's nothing on this board they could really use 200 milliamps at the point in time because we're not entering an s3 State yeah there's no it nothing in an s3 State here so it doesn't quite make sense what the eff is going on here well I do still have this thermal camera here that I have not unplugged yet and since it is right next to me I might as well make some use of it so if you direct your attention to the screen you will see a thermal Peppe thermal Peppe is the god of short circuits king of the Andals in the first frogs king of protector of the realm okay now as you can see we it's about fifth yeah 50 Celsius is being used right over here and if we turn the board around you'll see that what is getting boiling hot is the platform controller hub chip now the platform controller hub chip is powered by PP 3 V 3 S 5 in the beginning stages of the Machine turning on and the TP 3 V 3 S 5 is a rail that's created by the chip we saw and it's told to be created by this chip over here which is the SMC so the SMC tells this chip create PP 3 V 3 S 5 the PCH tells this chip create PP 5 es 3 so this chip is doing fine it's not that the PCH it's not that the that chip creating the five and three volt rails is bad it's that one chip that's supposed to be telling it to do what it's doing is doing its job and the other chip that supposed to be telling it to do what it's doing is apparently seemingly burning just sitting here and burning so we had one machine tonight that had a bad PCH that did not have a bad PCH originally it looked like one cap but then was bad PCH at this point we have yet another machine that is a bad PCH which we're going to leave in the status for Paul if you need something to be worked on with BGA rework if you need the zomo if you want to outsource a job that requires browsing eBay and Aliexpress and golden chipset and all these other CIC vendors to fight to spend fifty to eighty dollars a piece on chipsets that may or may not work that take 45 minutes to solder onto the board that you cannot return if the chip that you bought was soldered before even if the chip itself is bad if you want those types of jobs that are only done on a commission basis to be performed live on camera with a zamo that is on Paul's s's desk don't delay send your machine to 186 First Avenue New York New York one zero zero zero nine Rossman repair group attention Paul if you have a pedantic repair job that will likely waste hours of time and and not only not make money but cost money to do send your machine to rossmann repair Group attention Paul Paul is soon going to have as AMA on his desk that he's going to be using to work on all of these lovely boards that are just so easy to fix it just needs this needs a little bit of your soul so this board has a dead PCH which means that on a machine that is this old given the amount of work that would have to go into replacing the PCH thank you very much and well I really appreciate that that's very kind of you the on a machine that is this old that is a complete and utter waste of time because even if you do win and spend 45 minutes replacing a single chip after doing all this diagnostic work even if that chip does work which let's face it it it is eBay it is CIC it is golden ship said it is China it's not even if that BGA chip you get does work that's quite a bit of time you spend to fix the Sandy Bridge and at this point with the amount of time I've wasted tonight and the amount of no fixes I've had I'm feeling quite sandy as well so let's go over before I end the stream and ride my bike off the Williamsburg Bridge we're going to go over why it is that pp3 v3 s5 was being creative at PB v es4 was not so we're going to take a look at that signal that was we were required to get P P 5 vs 3 working P 5 es 3 enable L needs to be low remember so let's see where PBS 3 enable L comes from P 5 es3 enable L this is going to be a signal over here that can be pulled to ground and made to go away remember the signal has to go away it has to be low in order for the P 5 vs 3 to be enabled so Q 70 911 is an n-channel MOSFET that will open when the voltage and the gate is higher than the source and here the source is grap so it will allow this signal that we need to get rid of to go to ground if there's voltage in the gate and the voltage in the gate is going to come from p.m. sleep s4l p.m. sleep s4l comes from the platform controller hub over here and the platform controller hub is the chip that I just showed you on my Peppa thermal cam as being on fire so we have p.m. sleep s4 now going out of you 1800 u 1800 is platform controller hub and if we take a look over here you'll notice that platform controller hub when we plug the board in we're gonna take them next safe do this ahh 57 Celsius and it's not even on this is junk complete and utter junk I'm going to go cry now I'll see you in the next stream and as always I hope you learned something

Channel: Louis Rossmann

Views: 159,314

Rating: 4.9167547 out of 5

Keywords: macbook, logic board repair

Id: Cn7iFO1TNEw

Length: 27min 12sec (1632 seconds)

Published: Sun Apr 28 2019