How to diagnose & repair a phone charging circuit - Samsung s10 dead, not charging repair

hello so we are back and this time with a phone repair yeah so this is not a data recovery it's a phone repair now I will show you three ways to figure out the fold before opening the phone now was that inference video data recovery in a phone repair like usual for a 40 pair the repair is quite cheap or a body pair they say a body repair okay not a funny pair of board repair like this one this is a Samsung Galaxy S10 it's not coming on and the customer is saying uh he's his friends front phone and the one tour none and no one else opened the phone oh which it's a good thing okay so what's the difference the difference of data recovery you carry on how much you can yeah yeah the the data recovery is charge per hour a 40 pair how much time I'll spend on a phone repair not more probably than a half an hour or let's say one hour if I didn't figure it out in a half an hour I'll stop okay I mean it's cheaper just to replace the board or anyway it's not worth it's it's a cheap job personally I charge 60 pounds for a poor repair phone board repair so it's very important the diagnostic yeah just to work with this time I mean I I gave you a price for a country like United Kingdom on a different country you can afford to spend like 10 times more time because the economy is different I'm just giving an example now three ways to check a phone first way this is the simplest way you plug the charger you plug the charger and the you know you see nothing and you can't figure it out the fault the phone is displaying nothing you can figure it out default no the phone is dead then you have no idea what's the problem okay the second step is adding a USB meter a USB meter yeah USBC meter you plug the USBC meter and the USBC USBC meter is restarting which italyu is something is wrong but what is wrong is it doesn't tell you it's telling you like okay sorry something is wrong it's not charging okay but again you didn't figure it out was the problem now my favorite way to check this with a normal USB 5 volts normal USB we have here uh let me light up the we can see the voltage you see the current this is five volts yeah so this it will not restart if anything happening you know the the voltage it will just go down let's say in a case of a short circuit it's not you will not have restarting or things like that yeah so plug in the cable on the phone and you see this is a different story that's what I like to check with a normal 5 volts power supply like I have 5 volts from a iPad plug 2.4 amps so you can see the voltage is stable the answer is fine it's taking around 0.1 with the voltage is jumping and jumping voltage we learn in the past can mean a short circuit onto the board not necessarily a short circuit but clearly I can see more about the phone so what I can see I can see the charging port is good I can see the power is going into the phone yeah and I can see the phone actually is reacting and is trying to do something it's not that voltage a dead current like that current is like a fixed amount of current and you don't really have any idea about what's going on there but jumping current is telling me a power supply which is trying to do something is trying to start yeah and he can't start from some reason or something else but the phone it's alive I can see based on the the jumping car and I can see the phone it's alive yeah so what I will do the charging port is fine like how I said what I will do I will uh start the heater and I will remove the back cover of this phone and let's have a look inside yeah so see you in a minute okay so the phone is over we remove the back cover okay and now all we have to do is to take out the screws and go inside of the phone yeah okay so we remove the screws now another another important uh step is checking the battery the battery can tell us a lot of things yeah so we just open the phone um we can test again we can test with the USB meter again same behavior yeah like 0.1 milliamps and the current is kind of jumping yeah so it's same now the battery can tell us a lot of things like you have a fully charged battery that is kind of normal to not take any current or if you have a fully discharged battery like fully discharged like even under the discharge level yeah the minimal level sheets around 3.5 volts or 3.4 we have zero vote yeah so let's check with the multimeter let's check the battery [Music] and you see this is a case we have zero volts on the battery you can see at the like zero zero it's under the minimal uh level so what I will do I'll take the power supply uh only the current around one arm for the beginning let's say minus and plus you can feel it on minus and flashes to just switch on the beeping mode beeping mode you have ground and here you have plus here you have ground that's mean our ground our ground is here okay so here is ground here is Plus and I'm trying to charge the battery and the battery is charging check on the screen one amp and the voltage is going up is 2.8 volts 2.9 you can see on the power supply three volts 3.1 now what I will do I will raise the current yeah let's raise the current to about 2 amps you can quickly charge basically any battery with 2 amps for a short period of time of course we have 2.1 amps the voltage is 3.4 3.5 now with two arms yeah uh like you think now okay sorry so 3.6 volts I mean the battery has 3.6 no 3.6 is the voltage which is on the power supply but from there you have cables you lose some voltage and some current there then you have the battery electronic board you lose some voltage and current also there so uh let's say with two amps when the power supply it'll say 4.2 volts the cell the battery it will have around 3.6 real voltage okay so that's the that's kind of the the translation yeah so on the power supply is only 4.2 the battery should have like 3.6 yeah the battery is very very discharged and what we see that jumping voltage means a power supply which is trained hardly to charge the battery and you can't charge it I found before like battery stuck on a very low level and when it's a very low level on the battery the phone it will not charge like normally it will charge with a very low current and some batteries cannot be taken out from that stage with a very low current yeah you need like proper High car like on this case I'm using like two amps 3.8 volts charging slowly probably it will take a while I will edit the video you know what I can tell you the but this battery is quite good I mean you can check the internal resistance from what you see and this battery is quite good quite good so I don't understand why the phone goes on this stage like the battery probably the customer left the phone for a long time without charging can be yeah the battery goes very low and you can charge anymore but I don't think here we are speaking about faulty phone we are speaking about stock battery uh uh the discharge discharge stock battery otherwise the current even 3.5 I can push into the battery even 3.5 amps and the battery is taking it you can see the battery Eternal resistance is low you can see the voltage like 4.4 there so on the battery should be even lower battery probably has like 3.6 right now we can check that let's check so the battery voltage is 3.7 that's good that's great now let me check if it's charging with this one but I need the Wi-Fi antenna foreign volts 0.6 amps a percent foreign with what I'm I'm seeing here okay if I'm not happy I'm not happy five volts 0.2 0.2 with 5 volts I get like 0.2 amps which is very low I mean is that very low let me show you the different uh plug yeah okay it's the charging current uh doesn't make me happy I mean with five volts the phone is taking around 0.2 amps which is very low and you can see kind of the phone is charging but actually no really not a 0.2 amps here I can I shouldn't see I'm expecting to see like two amps yeah like 10 times more current so uh let's try and do some research about this so the first thing what we have to check if is the phone is taking five volts inside maybe we have the phone is losing the current on the charging port yeah so you can check here from here and the input and you can see on the screen check on the screen 5.1 so the charging port the VCC line is fine but that's not enough kmbi issue with the data pins yeah I don't believe it is but can be okay let's go into the board and have a look a little bit on this chip yeah hopefully it will uh hopefully a Reflow it will solve our problem okay let's go and have a look for this ship u8031 okay so that's the board and the chip is somewhere here so we have to take out this now we have to remove the shield when we remove the shield let's check so we have this chip and this has a heatsink over you can see usually the components they are getting hot are most likely to fail so I'll be using a little bit of flux around 370 degrees just a shorty flow and the chip is moving clearly the Reflow has been done now all what is left is the test foreign probably I have to replace that chip let's cool down the board at least a thermal so I will use some thermal pad it's getting cooled easily good let's connect the wireless charging antenna now let's connect the charger I have a 0.26 and they show you charging were I'm not happy with that the current is too low the current is way too low it should be around 2 amps yeah okay on this point all I want is to replace this chip okay which is managing the charging now what you can check on the board I recommend you to check this yeah so you plug in the charger yeah we don't have battery you have one you can check if you have input it's very possible let's say okay um I'm not sure where the 5 volts is I want to see if my 5 volts from the cable yeah is going to the to this ship yeah it's not like okay I want to check from here here no I want to check from here to here yeah so the the way how you check anyway on Samsung S10 but basically on any phone that's the best test what we can do here to see if the if the 5 volts is reaching uh actually the the the the charging the chip and on this one uh I believe here yeah here you can see on the screen we have 5.1 volts yeah so 5.1 and this ship is meant to charge the battery so we have five volts on that chip so what I'm gonna do is I will replace this chip it's a mark 77705 I believe yeah yeah that's the one I mean it looks like this ship is faulty so I tried this old a Reflow I try a Reflow and a Reflow I fix a lot with just the reflowing and it didn't work so I'll replace this ship so I will come with the I will come with the hot air 360 degrees I'm using Celsius and we're gonna replace this ship without reboiling okay so that's the chip we remove the chip the cheap position okay now what I will do I have another board here I have another board here this one this is a faulty board and uh yeah this is 10 plus it's not the same but must have same chip here okay so everything is clean and tidy yeah let's see the chip and the chip is nice now a little bit of flux perfect as long as you get the chip the cheap position like that good unless I love the chew back okay so the chief went to his position okay everything is fine now let's cool down the board and hopefully it will work now let's see battery charger and this taking one amp checker yeah of course you don't have the wireless antenna but let's plug it back and check last plug this for the board back and the wireless charging antenna foreign we have one amp 5 volts one amp you see one up I mean I did expect to see two amps but I believe probably because this is a Apple charger you want Samsung but anyway one amp compare with 200 milliamps yeah so that's the catch now probably if I go now with the USBC if I go now with the USBC let's see the current I'm curious so with the USBC with the USBC let's see the car you remember it was like 9 volts and 600 milliamps you remember and we have we have 8.8 1.6 amps you can see so clearly this ship was burned yeah the max one that's why it's good to have like spare boards you can you can anytime you need a cheap you desolder the ship and you move it to whatever whatever you need yeah where do you need the chip so this one is fixed yeah because that's the right amount of current again compared with the compare with the one with the five volts what we I told you to check yeah you see one apple I will put uh all back together hopefully it's coming on show come on it is coming on okay I'll put all back together because this is a hundred percent repair we have to clean the camera to make everything nice we have to put the the Shield back the heatsink back on the CPU so all we did we replace the the charging I see yeah the max chip here you have to be careful especially on this model because you have the flash next to this chip okay so let me put all back together see you in a minute okay all done I put I put the phone uh handle back together it's taking like one amp from the normal charger and it's taking let's see yeah 1.6 amp with the 8.8 volts okay so uh you see this is a this is a case where most most of the people on the repair business what they will do or what they will say because I know what I've seen on the past on the comments they will check with another battery that's what they will do and the problem is the battery is very easy to test and I made so many videos explain you know the relationship what you see on the power supply between the voltage current and actually the the voltage of the battery yeah so it's very easy to figure it out if the battery is good or not and we have the back cover the back cover I need some I need some glue but the phone is like new no scratch nothing perfect okay so uh don't blame the battery I mean don't blame something what you think it is yeah I I think I want to check on another battery no yeah it's very easy but you can check the battery the power supply the the battery resistance is low it's fine even if the battery internal resistance is high if it's high you can have that kind of reading yeah like low charging current but that's why you have the power supply to test the battery I figure it's one second to figure out if that battery is good or not I made the videos and I explained how you how you can check okay so I will stop now uh you know what I was I swear I didn't expect this video to be that long I I was thinking I was about to swear actually all what the problem was with the phone was a very low battery because I had in the past like phones just with zero volts battery just charging the battery with the power supply the phone come back to life we we try and chat was charging fine working fine so the only problem was the battery no one charge the battery and the battery goes like to zero volts but not this time this time we have like a like a burn chip yeah so even fast charging is charging fine okay so I'll stop now I will say uh thank you for watching like And subscribe if you like the video and uh you know just try to pay attention on the details just because it doesn't charge that doesn't mean it's the battery it doesn't mean it's just a Reflow job or just a cleaning charging port no sometimes there are burnt chips you know like on this case the charging tube so uh thank you for watching like subscribe if you like the video and see you in the next one bye

Channel: Electronics Repair School

Views: 37,954

Keywords: phone repair course tutorial guide, phone not charging repair, phone not coming on repair guide, phone microsoldering, how to fix a dead phone

Id: ddJbx95Fvlg

Length: 30min 12sec (1812 seconds)

Published: Wed Feb 01 2023