iPhone XsMax No Display--Multimeter Troubleshooting for the Win!

Alright, today's case is an iPhone 10 max that has no image or video, nothing on the screen. Now I will do this case on video because there is more than it seems, it is a warning that sometimes what it seems could be the problem. is not always the problem. I'll remove the screen, disconnect the battery, remove the screen and then we'll take a look under the microscope. Now this phone came to us like, oh my God, during a screen chain. Without imaging aid, they told us that they could see that something had come loose from the LCD connector, so let's start there under the microscope and see if we can notice what they were talking about here is the LCD connector and yes, it appears that way. like there was some kind of party in this area so we are definitely missing a component here and then we have other places that may be missing something but those also couldn't be things or places that have solder paste but never they intended to receive a component with skip points, so it's hard to tell, but this one here is definitely something removed, so our next step is to say, well, that'll be it, obviously it'll stay. silly again there, but before we do that, let's look up and not only see what is there, but also think about the function of what is missing, okay, so at zxw let's take stock, we will definitely look for the identity of this guy gone. so aha, our missing guy then it will be this one here C 57 82 is missing which is definitely missing and it's a capacitor on a line that says P P 1st screen that sounds like our gas would be energy for the image, but a capacitor doesn't It doesn't have a online function, so it's more like a grape, so you can pluck a grape from a bunch of grapes and it doesn't really have any practical effect, you can't tell, that doesn't suddenly stop being grapes now if you have If I had than cutting an in-line component then you'd have a bigger problem, so a capacitor in general is unlikely to cause a complete loss of function simply by falling out when it's a tiny capacitor in these areas, so that doesn't really seem to be the case. a good candidate to explain why we have no image, so what else is around the missing filter?

It's definitely missing, but it really bothers me how rounded these pads look. They've been investigated a bit, but these pads don't look like a disassembled component. Compare these guys here, the missing cap looks like a disassembled component, but even the one next to it has rounded, beaded pads. too professional and they look like something that was never there to begin with, something that is known and that is what is happening here in this filter and in this adjacent place here it seems to me that the only thing that was really knocked down was the capacitor and that doesn't really explain our problem, so before we start putting things in here, let's stop and think that a lot of times you can get a little bit more detail from the schematic itself, so let's go ahead and see if we can do something like that. understand the role of these things so the schematic is fine so let's start with the guide which is obviously removed so that is our small missing capacitor and our small missing capacitor is C 57 82 so let's understand what to see fifty and seven eighty to do first and then we'll look at the other guys that are missing, so in the outline we can write C fifty-seven eighty-two.

Now every time I show a schematic everyone bombards me with questions where did you get this schematic and this one was fun. because of the 10s max command, I think almost everyone I know got an email one day saying that the iPhone 10 max schematic is available on eBay, click this link and there was a guy who was trying to sell the schematic for $100 on eBay and that was It's crazy because everyone who works in this industry knows that once a schematic falls off a truck in China, it's distributed around the world in a matter of seconds, so if you're looking a schematic, maybe you should be able to google the license plate number or just look. around using regular search tools and you will be able to find it if you can't find a scheme you are looking for, it never fell off a truck in China so it has no real use, you know, there is no such secret treasure. chest of all the schematics that everyone knows about, but they are all commonly available or not available at all, so let's find our guy, see 57 82 and try to get an idea of ​​what's going on here, so see 57 it's 82 it's on this page here with the

display

flex connector, so this is the connector and we can stare at the connector and see, okay, I see some power lines, they see some data lines that are probably all important so that the image works, but let's look for Where is C 57 82?

It's specific and here we see that C 57 h2 is in fact a capacitor and it's a small 220 Pico farad one which is incredibly small, practically nothing and it's on a line called screen pp 1 Bo, so it sounds like a power. line with a vote of one volt that would probably be required to show now this guy here FL 57 82 is zero ohms and it's drawn as a resistor, so that's something I want to draw your attention to so you can see these FL 57 filters 83 and 5780 this is FL so you would think it is a filter and that is typically the case but when we look at even the board we can see that FL 57 82 is in fact a resistor so let's look at the actual board because that guy is still present so I just want to show you that real quick here is FL 57 82 is a zero ohm resistor and let's check to make sure it's present on the board and has continuity so I'm going to turn on my

multimeter

and since I'm just testing hey.

Are you a cable? I'll put it in continuity mode and just test it. Hey, are you a cable? This is, yes, I'm a cable and you connect it all the way to the connector. Yes, so we have an intact line from one side of FL 57 82 to the connectors, so look at 57 82, he is not our problem, he can be eliminated and that line won't care, so let's keep looking to see what happens with the other guys in the area, so let's go back. to look at the microscope and see the other guys, so if we're going to say, I just don't think that guy needs to be there to be able to visualize it, but what about the neighbors?

So we miss your next door neighbor. and we're missing a bigger component here and we're missing this little one and we're even missing this square guy here, so let's see if we can find them all, so let's first quickly grab their ID eight, so who the hell are these guys? Okay, so we're also missing c50 706, we're missing FL 5781, we're missing our 57 20, and we're missing a chip, you 5701, but everyone seems to know things that I now want. to get your attention also when it marries it's exw zxw doesn't recognize any known elements so if a component was skipped and never placed on the board that's really common, the XW just reports it as if it were there so that zxw is a is incomplete, so you should always do it if you can get the rich data set from the schematic that will give you a lot of clues and help you make a lot of connections and work better, so let's go to the schematic and see if we can see what happens. with all these types, then we will find C 50 706 on the schematic itself, show yourself well, it is also a small capacitor now, sometimes the schematic says there is nothing this time, so it's a bit trollish, I still think. that that's a knowledge component and then we can see our missing type FL 5781, so it's missing a filter which should be a big problem because that would mean we have a dashed line here on screen P p1 v1, so it looks like this .

It should be a big deal, but it doesn't look like it's ever been there, so this is a bit trollish, which is why I want to make this video. I don't think anything in this section is relevant to why this device doesn't work. I don't have a picture and I'll show you why let's look back here, this is the chip we're missing 5701 and try to guess what this chip does. This chip is simple, it has one input and one output. it has an enable so something tells this guy hey get to work and it will take an incoming voltage from a v26 and convert it to a very specific output of a v1 and this type of guy is called LD or which is a conversion mechanism. voltage A to voltage B, but here's this little, this is the kind of rich I'm talking about in the schematic, so it tells us you know, hey, guy, 1.2 volt LDO, that's this guy , this type is for the LG C and I am not.

I know what that means: LG sees something about one of these screens, how the screen works, the LG C test chip, once the normal panel is available, then it switches to 11.1 volts, so that's a note of design that, like, hey, this here is going to be changed or if it's now releasing 1.2, it's going to be 1.1 and now when we see that whole system seems to be missing from the dashboard, you know we're looking at a screenshot of a day's schematic in development when that schematic fell off a truck, we don't know what happened after that, maybe someone came and said, you know, forget this whole section, we'll do it a different way, so you have to be careful with these things and be aware, and that's it. what this video is about so this whole bit was removed so this resistor that is missing the resistor was always known and this chip is missing which means this output is never generated the chip is not there , it cannot be generated and since this output then it does not have a chip to generate it shut up and since this output cannot be generated then of course it does not matter if FL 5781 is there or not so it is not placed there and then Of course, look. 50 706 doesn't matter either, so none of this matters, none of this matters and it was never put there at all, so it's also not relevant to our problem, so what does that leave us if we look back at our current state? board now we know, okay, we're missing a chip, now that chip didn't drop, someone tested it here, but it's missing because it was never there, so the chip was never there and this resistor that goes with that chip was never there and this filter that goes with that chip was never there and this capacitor that goes with those guys was never there so it was never there it didn't fall out it's not part of our problem what broke doesn't really matter there's no mechanism where a tiny little speck of a capacitor that barely does anything, I mean, think about what picofarad means.

Pico is a 10 to the 12 of a ferret, you know, this is a million times less than a microfarad, which is already 10, so it's basically no dust at all, so that has nothing to do with our problem, why don't we have a screen? And of course, I have followed rule number one, so I have verified that the screen works on another Maxo sneaker, it is not. part, then we don't really have a screen, so how are we going to find out what the problem is? Because the problem is not here, it has nothing to do with this physical damage.

Okay, our next step is to compare the broken

iphone

tennis max to this good tennis max now this is a phone that belongs to the business manager of iPad Rehab on Sunday, so we disassembled Sunday's phone just to get these normal diode mode readings or the normal values ​​on the lines on the screen and people ask me everything Right now, why do we use an iPhone for this reason? So we can take them apart and we can have this information that we need. We didn't have a known asset. It would be really difficult to find out where the problem is. because you don't seem to have it, it doesn't seem to match the physical damage, so I'm going to show you very quickly the find here so we can save time, but just to know that if you have a case like at 1200, our phone crosses your desk, then go ahead and Take the significant diode mode measurements and share them with everyone.

You can go to the iPad rehab communication, click on our forum to go to the "it takes a village" section and upload your diode mode measurements for the latest and greatest phones, that's what I'll do right after this work for the 10s max LCD connector so for now let me show you with the

multimeter

and I will look under the microscope and show you. that's a good one, so it's a good maximum tennis that there's nothing wrong with it and we can see that there are no things in our same area either, we see how our chip is missing and we can see that there is a flat area.

There's nothing there in that spot either, so let's go ahead and air out our resistance measurement instead of actually measuring ohms to ground, since that takes a lot of time. Let's infer it using a diode mode measurement that we use all the time, that starts with the red probe on the ground, so I'm going to place the red probe on any ground like this screw hole, not on the frame, but on the land of the board, and then I think the problem is somewhere over here and over here at the bottom of the character we get this dot five dot five land dot five dot five land dot five dot five so that kind of line line land line ground line when they are all the same that is really characteristic of the

display

connectors and those are the image data lines and they come in these paired sets and they arebordered by the terrain that's on every iPhone, so we know it's going to be image data, so let's make sure it matches on our dead phone, so I'm going to check the exact same spot where it is so the area looks good, but let's check, we'll do the same thing with the red probe on the ground and we should get the same number so you know roughly point five, same ground. you know, the same point four seven point four seven earth 0.47 whoa, what's our problem, this should be point four seven point four seven earth but it's not and two of them oh l-o-l overload or open line because there's a huge amount of resistance that can't go back to that normal diode mode now they're both open line and that's why we're missing that kind of pattern where it's data line you know data line positive data line negative ground data line positive data line negative ground data line open state open line ground line so I figured that's our problem right there and since there are two of them that are open we're probably missing one of those classic little data jokes you find inline between the connector and all the way back to the CPU, so let's go.

In a search, let's first confirm that we check the schematic and make sure that the iPhone 10s max, which I have never seen before, has the same feature as all other iPhones or not, so let's see the schematic. just to be sure, here we are in the schematic and we can see down on this side, it's exactly as we expected data line P and ground P and ground P and ground, so these are three on one side of the connector and then two. of them on the other side of the connector as well as any other iPhone and then on this same page we can follow these guys and they go here to this set of what we call data chokes, so if they are like double filters where Keep these two lines together and it's like a filter created for two so they have certain data that if we wanted to order one we could probably find an exact match for that if we wanted to order one to replace it so Our assumption is that we have an open line here on these two guys because this filter has probably just been pushed, bumped, or exploded, so let's investigate it and we'll go hunting to see if we can dig it up.

I'm going to try not to dig and see if it's actually damaged or just lifted up, so that's very likely what's going on with this phone, so let's check it out on the dash, so I'm going to use that. a little bit of slow heat to dig around this area safely, let's open up these other connectors first. The beautiful tool that is fantastic for connector work is the human fingernail with its dynamic grace that can feel things like MI lifting a filter, you better not stop. tool, then the human nail is not available and I have had rehabilitation.

Supply C, so we can see right now the characteristic little square shape of this data and then look at that, see that movement, you can see this filter that is completely hidden. It looks great, that's the problem with the filter there, you can see that when I went to try to even do a measurement, I have movement, let's check it, let's test anyone, you're not on your pads, now you're moving? that you're not supposed to do that, yeah, so we can see that inside the waterproofing underneath, that guy's loose, so let's bury him gently, let's sneak up on him and extract that waterproofing heat just from the hair dryer, we're just going to try release it. let's free it from the corset of this waterproof silicone, okay, not okay, it's split in half, but this is really cool, this is a really cool insight into why we say this leaked word in our industry and why We say we say that because these components are in the inductor class and all inductors have a coil of wire but no inductance, they do not function as an inductor coil.

When we say coil, we mean an inductor which is a coil. of wire which has the characteristic of inductance for these types we refer to a filter which is also a wire coil and also an inductor but they are used in the circuit differently and we can see it in this rare unicorn view of this choke of data that is a double filter we can see the cable coil, we see that it is not good, although it is not good, so the iPhone 10 has a very similar component and we can check it, we can see that this is a row of the same data chokes and we can look at those values ​​and they're very very close to what's happening here on the 10 max, so compare that to the 10 max, the filter row is a very similar component, so we'll use one from an iPhone 10 and we'll put it in place here on the 10s max and see if that solves the problem, so these are not directional, so I can just take it and I can control C control V to the 10s max board and I'm going to put it in place using the mini. hot clamps now I'll know if we really have it there because now we'll have our normal diode mode readings on the connector, so let's check that red ground check probe and now let's go down this connector point by point by round. point by point by round and now point four point four round huzzah, that tells us that yes, this component is completely soldered on both sides, all four points are dropped, we know this because we have restored that normal reading on the connectors. clean this and the next step is to test to see if it works clean with alcohol and let's test well everything is connected let's see show me the image ah yes I love to see that here we go everything is working and we have touch and ready to be a beautiful $ phone again 1200, so there you have it, sometimes you have to use your brain, learn to use them, the multimeter, the multimeter is king, the multimeter solves more problems than anything else and I love this case, kind of an example of how not to be trolled how not to be so hasty it's not always so broke fix the broken end of the problem you know you have a sometimes you have to measure a little so there you go if you like what we do on our channel and you want to come and learn how to use the multimeter, how to solve these things, then come see us at the practical board repair schools, so in a couple of weeks we will have our master class that we will organize with Cong phone from China, they come to teach us how to do all the advanced stuff, advanced CPU diagnostics, I'm really excited about the master class, eight-day course that you can discover on the iPad rehab communication training and then if you're a beginner, come to the hands-on board. repair school our June course is full but we have places open for July for a short five day regular basics course on how to learn to do what we do and then if you like if you want to explore our Android option we have a course seven day course that also teaches you Android chipless data recovery and some Android signing issues so check out our training options on I pad rehab dot-com click on training read all about it and See you here in class.