hello so we're back and this time we have an urgent job I'm not gonna lie usually the computer shop this laptop is coming from it's charging 80 pounds for a motherboard repair but because the customer wanted today is 50 pounds on top so it's kind of important to fix it yeah and not only to fix it but to fix it today now that's a Microsoft Surface stop uh laptop but the laptop came here like I don't know the back cover is coming out so someone opened this laptop I didn't open so I don't know what's inside yeah so that's the laptop inside so we have the keyboard and we have the laptop now this has to be fixed today don't forget that yeah what this is doing I have no idea just assuming he's dead let me plug the charger because I have the original charger here okay so plug in the charger we plug the charger let's try to find the voltage on the motherboard so I'm not sure where we should check the voltage or check here the charge imported has a bunch of wires I never fix something like that we have light here check that we have light so it doesn't mean the laptop is charging where we can check the main power rail probably those capacitors right and we have nothing and nothing good power supplies those are part of power supplies and we have nothing and we have nothing okay where is the battery connected probably I can see the cable here so probably is going on the other side of the board not sure again here you have capacitors and we have nothing and here we have nothing so basically we have no voltage on this motherboard which is strange because we have the light on the charger what is this here we have 15 volts here so those are mosfets or what let's check together okay so we can see the input circuit right so we have two more sets check that here are together so what do we have here here we have nothing okay here we have 14.5 and here we have 15 volts uh 15 14.5 okay that's not right and on the gate we have 14.4 on the gate okay that's weird but the thing is after this mosfet I have no voltage and I don't know why so what I will do I will unplug the charger let's switch the actually let's not switch let's check the voltage because the battery is still connected you have nothing nothing and nothing no voltage let's reach the multimeter on the home range so on the on Range here is fine it's not short the mosfets this one is not shorted and this one is not shorted okay this looks bad the gates are fine so basically we have no volt we have we don't have the right voltage on the Gate of those mosfets yeah I believe those are Channel and mosfets we should have uh we should have 25 volts on the gate those capacitors no one is shorted so this is quite a strange food so probably this is the main power Rail and it's good it's nothing shorted here no nothing nothing no no shorted so how we can repair this because I never fix something like that no it's not short so do we have some BQ chip here somewhere or how this is working like a normal laptop how we can fix something like that foreign let's take the board out because I'm curious to see what is on the other side so this is some kind of hit sing because you can see it's part of the big heatsink I'm just curious to see if we can fix something like that I'm curious to see the design okay so the heatsink is coming out this is something what you expect to see on an Apple laptop it's a nice board I don't know what is here behind of those things okay so basically you have to open the hinge to take out the board right so it has to have probably some screw under one of those bits what is that oh this is a cheap this looks like a power supply chip foreign this looks exactly like a power supply chip maybe we can spot something quickly okay those are coils foreign I can't see anything wrong here although this is a big coil and we have a normal chip huh let's check what do we have on the coil the coil is not shorted no everything is fine you're all good here let's see next so here we have another power supply right now this is a Sunday no this is the song the area foreign supplies more power supplies let's see what we have here good good coil good probably some screen inverter and that's a fuse right which is not good wait this is an inverter and these must be a fuse or this one this one is a fuse but that one looks like a fuse strange strange okay and those are the screen connectors hmm yeah it looks like and here we have more chips we did okay so here we have more screen connectors screen touchscreen connectors right yeah and we have a screwdriver you can see the screw so we took the motherboard out LOL check here the the battery connector that's what I call a proper battery connector let's see the voltage the voltage on the battery is zero let's see the battery is taking current kind of low current minus plus and he's taking check that 1.6 amps let's rise to 3 amps It is charging with three amps yeah it is so the battery has like how much 7.5 is saying on the battery but it's interesting because the battery was disconnected so that's been either it was dead or it was a short somewhere so we push some current into the battery right so let's check the voltage on the battery seven volts still low or short charge check that connector that's a proper big connector let's see if it's charging I mean how can I know if you're charging or not I don't think it's charging but the main power is 7.9 wait so that's mean my laptop it is working on the battery but it's not charging that's what this means right I mean the main problem from the battery is present it's not present the one from the from the charger but the one from the battery it is present they are 6.9 okay so how we can figure it out what is wrong here huh what do we know we know the voltage gets stuck here somewhere so we know after those mosfets is no voltage right yeah here they have nothing and I don't know why now my question is this power rail is going this is the main problem let's see this is the main portal or not it's not so this is going to the to the charging port my question is this is going to the charge input yeah okay so the charging port is coming straight here okay then we have two Moses I'm pretty sure there has to be some current let's call me the charger so we have like what like 15 volts yeah low current like we have how much current we have like 60 60 million 600 million I'm sorry and let's see what is happening yeah we're coming with current here and nothing will happen yeah here is ground I mean it's taking no current at all nothing now the only way to figure it out what's going on here is to find where the output of the atmosphate is going so in this way we will know the power flow yeah so okay we know that we have two Moses yeah I got it but after the second mosfet where is going because it's not the main power out there has to go somewhere he's coming here to this chip foreign the Gate of this mosfet is coming here so you can see that's the Gate of this mosfet it's not the source it's the gate and it's coming straight to that chip okay so if you have this board have in mind this ship is managing the input mosfets okay and now we are focusing on this chip this is like on the on the MacBook the chip which is boosting the voltage yeah so this chip is creating the main power look at the coil yeah so let's pay attention and see what voltage do we have around this chip because we yeah we have 14.5 check on the screen so basically we have all these on this chip but this ship is not doing the job can be the chip can be let's see if we have input voltage on the mosfets and we don't in dust range now we don't have but we don't have voltage on the mosfets because the first or most threads are managed by this one let's see online what we can find about this ship okay nine two three okay if we found the data sheet of this tube yeah so input voltage system output voltage okay good so this is the schematic it's exactly like in the MacBook this small set which is saying is optional it's not actually there are two mosfets and we have a pin AC in which probably this is AC detect yeah how can I zoom this thingy how can I zoom it yeah from here so check here those thing is I know not this one no okay no no no here are two Moses yeah we we yeah I want to check this pin you see this is a divider so AC in AC in pin is where AC in his p number 19 yeah let's see so p number 19. 16 is here and they have 1.3 we have 1.3 volts on the ACN oh unless you AC Ian pin voltage is greater than 0.8 so it's fine yeah so that pin is fine so why is no working probably because the chip is dead I mean we had this one second we had this we're fighting let me find the schematic yeah this is this camera too you remember we had a HP laptop and the vdd pin was not 5 volts and we have DC in we should have voltage from the visual voltage so DC in and vdd DC universities next to the other lol 17 and 18. let's check foreign so this one is this scene and it's dead yeah dead dead vdd vdd we have 0.5 and again it's not good so why this speed which is DC and you know what is this scene I'll show you what is this in so DC in R2 diodes you see so one is coming from the system from the battery and one is coming from the charger in this way this shape it will always have power so this in voltage has to be it doesn't matter 12 volts here so I'll call me the power supply DC in DC input of an internal ldo yes yeah yeah so it's it's powering the internal ldo connected your diodes from adapter and system outputs okay so should work with any voltage with any so let's come with 14 volts then and see what is happening he's taking 600 milliamps long why is taking 600 milliamps and the voltage get dropped to 2 volts let me lower the voltage 600 milliamps let's let's get a thermal camera quickly so what is taking 600 milliamps is my fault with this board doesn't mean it's burnt so I said this resistor right bro any other ground there's no ground right no it's no ground there's no ground he's not ground I swear those people are like apple they don't put ground on the holes check that what is getting hot so DC in the chip is shorted yeah he's dropping the voltage to to three volts and it's taking like 600 milliamps so the chip is dead now I'm not sure if I have the issue but let me try and find it yeah let me try and find these two yeah the problem is I don't have the chip so I have to order the chip so what can I say so I'm gonna stop now and they're gonna fix this next time right we found a problem yeah we found a problem yeah okay just I just realized yeah so basically I said we found the problem yeah so check here if this voltage is missing my diode is burned also yeah so we have a double diode here double shotkey diode so the diodes are burnt and also I need that double diode yeah okay that's not a problem next time yeah bye okay so we are two days later and the parts arrive check here very proper nice you know the Mauser uh they are you know packaging a proper nice way everything so every time I get the the parts like that expensive but nice so this bag probably is for only for one chip huh all sealed it's like buying a ring you know what I mean yeah so that's our chip good and I bought some dials and I bought like three dials just to be sure I have in the future yeah so those are the double diodes they are cheap you know the parts are cheap are not expensive but the postage is like a little bit over 10 pounds because they are sending the parts with FedEx okay let's replace let's replace the ship and the Double Diet so the notch is there the notch doesn't have a mark so we have to keep it in mind just a little bit of flux so I believe this is our double diode not sure bubble check good so we remove the old chip let's come with a new one hopefully it will get solder yeah he's fine a little bit of flux okay let's check about that double diode so if I remember this pin right has to go here and it's not going uh-huh ah no no no no no check that check there check there check that you see that resistor you see has a bump on it so what is happening here so probably the diode is going here yeah and resistor blow up and resistor has to go here yeah that's mean my diode can be good let's check good and good okay so the Double Diet is good I ordered a double there for nothing now let's remove the resistor it is important what the resistor it is no really so we remove the resistor let's have a look for another resistor so what resistor do you think we should use huh 100 ohms it's a little bit too high right 100 ohms yeah let's see something else three ohms three ohms it's above right I mean I'm not sure but it's a power L you know what I mean this resistor is meant to get burned in case the chip is getting shorter and also uh you know it's just uh limiting the current in a case of jumping voltage or jumping current but actually jumping voltage it will limit the current I always told just because the manufacturer use a specific value of the resistor that doesn't mean you have to do it you understand manufacture is seeing on is designing the schematic on a certain way and you can redesign it on the way how you see it yeah obviously it will do the same job I mean obviously it will work but I'm curious to see if that's all was only the problem so cooling down the board let me grab the charger okay so we have the charger and I really really want to see what's happening here plug in the charger let's see the voltage that's the first thing what we have to check the voltage I just want to be sure the board is not coming on so the voltage on the coil is nothing our Lord okay the voltage on the on the resistor is replaced yeah 14.8 you can see on the screen so we kind of fix the problem but still I have no voltage remember here we should have our main power here so we have like 0.5 and I'm not happy with that if I remember from the last time we have to check the internal ldo and the internal ldo so let me see on this pin we have 14.8 internal viewers I think here and has to be like 5 volts and it's like one volt and that's not fine over here here is 5 volts load okay everything is fine then we have 8.8 here one second maybe it is working I mean otherwise you remember we didn't have any voltage so you have 8.8 doesn't mean the voltage it is passing the way so the main portal is actually 8.8 huh let's check the main parallel 8.8 the main portal is present you know what I think we're done here I think we should test the motherboard so the map already is present exactly what we were looking for right yeah we were looking for to get the main powder present and now it is now the hard part is to put all those things back but you know I'm just trying to give you an idea about the approach on a case you are you are working for the first time on a motherboard yeah I never fixed this this kind of motherboard before I know it's looking complicated but remember what I told you most of the phones they are on the power rails and uh that's what you have to focus you know just getting your main power rail present I can't I can't feel the CPU hot and that's not a good sign but it's Microsoft so it can be different can be like when you press the power button so the board is not coming on itself so the CPA is cool the spinning developer is not working now I'm not sure where is the power button probably it's on the keyboard let me plug the keyboard yeah the power on it is on the keyboard and the keyboard has to be plugged where anyone's can see where is the connector here so pressing the power button I can't believe we have picture that's crazy and the CPU he's like like it's like warm you understand what kind of efficiency is here so I have the I have the CPU without heat see and it's like one now I started getting her no no no no no no no you start getting hot uh let me disconnect it yeah I can't believe it's working that's crazy LOL all good good let's test it one more time they hear me plug the charger let's plug the keyboard you remember this laptop came without [Music] with the keyboard removed so it's no problem to stick the keyboard back power button on the laptop it is coming on loading the windows the phone is spinning not no yet it's not even point I mean and the laptop is on huh yeah the mouse pad is working everything is fine okay good let me Shut It Down It is charging the battery okay good so we'll stop now uh not sure what model is this one seven six nine what my West surface is this hello Microsoft Surface 1769 come on that can't be true right I can't believe on what I worked I can't believe so actually I pay for the parts exactly how much is a new motherboard oh okay it's faulty uh so actually it's not that expensive Lord the whole laptop is like 200 pounds 165 pounds SSD 40 100 pounds it was looking like a brand new laptop like something very new well okay so one more time I will point this yeah it's no point setting the bar low yeah just because you never work on a laptop I mean yeah you can also maybe you can't fix it but you are still left with the experience so you understand you are still getting something even if you cannot ask for the money for the repair yeah if you don't fix it the experience it will you know accumulate and at some point it will be helpful okay great fantastic hope you enjoyed the video if you are looking to support this channel don't forget you have the YouTube membership and you have patreon description I will say thank you for watching like And subscribe if you like the video and see you on the next one bye