Customer sent a Huawei D14 board for repair, i fixed it, but didn't work. What went wrong?

hello so we're back and this time we have a nice laptop to repair trust me this is a very strange job so what's the story this laptop yeah it's very weird so this is a customer who came on the shop on the shop I wor before and he said he's looking for me anyway if the customer is not opening like a service request on my website is not my customer is the shop customer um he left the motherboard he left the motherboard to have the charging for repair now I'm not doing videos with every repair yeah so this uh this uh board was fixed the charging port was repair and usually when I'm do these kind of jobs where you cannot test it yeah I sent a picture to the owner of the shop yeah I sent him a picture with a meter yeah 19 volts you can see so that's the port which fix it 19 volts so the charging port was fine the light was present and I told him show this picture to the customer this proves the job was done properly yeah and that's the way how I'm dealing with the B repairs I done my job I fixed the charging port but you know it's not up to me the you know if the board is working or not the customer ask for a charging for replacement anyway you can't test it you know what I mean so you have to fix the port in order to test the board the board uh the customer took the board uh he test the board and the the shop called me uh the laptop is not working so he left the laptop fully for repair now it's interesting if you're are plugging the charger you seen the picture yeah good 19 volts was on the picture here is 5 volts so what happened uh what happened because on that picture you know 19 volts means you have a healthy PD controller it looks like a healthy board but this one with five volts it doesn't look good so you understand why this job is weird yeah that's why now I'm curious why the board is not working and what happened what happened with the board I mean it was good now it's not good how' that happen I did a bad job h I don't think this fult has anything to do with it with the charging port but we're going to see we're going to see okay so the laptop it's open and that's how uh the laptop is looking ins side I don't know if this is the board I fix it or not I we have to turn it on the other side to see if indeed does the board but let's unplug the battery yeah I'm not I'm not comfortable with the battery plugged in let's plug the the adapter because that's how I test the laptop here with without the battery so without the battery we still have 5 volts H so this is strange strange strange okay let's check the main power L just you know some basic uh checks on the board okay so what's going on here we have the capacitor on the main power L 1.4 ohms yeah so short what do we have here here we can see the the path yeah the path of uh of the the schematic yeah coil chip capacitor 1 ohm yeah good here we have not sure about this schematic if I'm not sure we're moving forward here we have 1 oh yeah here we have 1 [Music] ohm and I'm assuming this is the main power L is not so the main power ra is shorted right here we have a current sensor here is good after uh we have two moset check here we have two mosfets here then we have two mosfets here so this is the the coil which is Crea the main power rail so the main power rail has to be here 1 ohm so you see something happened from the point the customer took the motherboard from here and he put the motherboard back should we open and check if if it's the same board do you think the customer swap the board hm let's check because you know it's quite hard to like you know short a main power I mean it's quite a coincidence the customer took the job last week so from the last week till now he got like what like a shorter capacitor or a shorter moset weird so let me take the board out okay yeah that's the board wo that's that's that's that's unexpected that's the mother board you can see the the charging port again I know this is a Huawei yeah but I didn't do the video with this repair I mean I know we have a video with the Huawei charging port but just a coincidence is not the same job so that was the repair I did and check that proper solid right yeah that's the repair I did also I also strayed the the charging port here you can see it I mean it was a good repair right so what happened why this board is shorted I mean I have so many questions the board was good what happened let's grab the power supply and let's find out because uh big feels bad you know what I mean so probably the customer knew the only problem is the charging port right I fix the charging port i t the motherboard the motherboard had 90 volts on the yeah I can show you the picture one more time the customer took the board and the board is not working what do you think the customer it will think you broke it exactly exactly exactly what does what the customer it think I mean one more time yeah 19 check that 19 volts you can see it's the same motherboard same one because if I seen yeah okay I saw I replace the charge report and the board is not working I will say it you know your board is still not working okay let's see so we took the board out let's check again with the meter just to be sure checking again with the meter 19 volts oh l what now the board is not shorted but we check together it was shorted it was shorted if I remember I think yeah it's supposed to be a foil over over this part right ah I can't believe so now if I check probably is not short yeah what do we have the cadis capacitor no he's not shirt this is a very unlucky customer so he forgot to put the foil and probably the board is touching with the is touching is touching this board right the metal because otherwise cannot be explained one more time let's put the back okay so the board is back right yeah it is now if I'm checking the main power L check that check on the screen one ohm if I'm just you know look how can I do it wait how so even if I leave the board it's still short so what is the short are the charging port how the short can be at the charging port is not sense because everything is covered with uh no it's not you know it is a shirt I will I will show you where one second let's get some uh tape uh the pins are covered with UV UV gel yeah so that cannot sure the things here so here can be the short here let's try one more time yeah okay so the board is on place is still short okay cannot be one second cannot be at the charging port because the short is on the main power ra after after the the this power supply yeah so it's not on this side it's on this side yeah so must be something else okay let's use some uh tape so now you understand why the foil from the back of the board is important yeah that's why so now the board is covered on tape let's try one more time okay so now the big question is with the tape on the back we still have short no short I can push it no short you can see now let me put back the laptop and uh test again okay so the motherboard is back on Place plug in the battery the battery is plugged let's plug the charger plug in the charger 19 volts but it's not charging because the batter is dead Let's Help the battery so the battery has uh 7.6 volts so 8 point something will be fine good current yeah 2.2 should be fine we have minus we have plus charging with 2.2 amps check on the charging current on the meter 300 milliamps 400 check check that 440 milliamps 800 milliamps 1 amp 1.28 so now the battery start charging normally that's how you bypass that pre-charged current so now the laptop is char I with 2 amps now let's see if it's working pressing the power button and the fan is not spinning oh it's working no the fan is not spinning no no no you remember from the last video when I hit up the hit syn so it's spinning only when in when it's hot when the CPU is hot and it's working fine okay so uh everything is fine so what we can learn from this kind of repair first is what we can learn is actually soring even if he's not doing a video he's still doing good jobs the second what we can learn is uh pay attention if you take the board out because not everyone watching those videos actually is fixing laptops but anyway if you open your laptop pay attention on uh you know things which doesn't look important like that for oil from the other side of the board which it is important another thing if you think it's a little bit over your hand just you know choose a repair shop to handle your repair now another aspect have in mind the foil actually from the back it's a lot better it's a plastic foil it's a lot better compared with what I have here like this kind of tape yeah so if you have something sharp can punch through this you know this is like normal electric tape so the plastic foil it's a lot better compared with this one but even this one it will do the job you know in a case the customer uh doesn't Choose You know to punch the keyboard or on the back of the laptop I don't know okay so I'm going to stop here I'm happy I help this customer I will say uh thank you for watching I guess subscribe if you like the video and see you on the next one bye

Channel: Electronics Repair School

Views: 19,497

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Id: OeFlGDIkwoM

Length: 14min 33sec (873 seconds)

Published: Tue Jan 16 2024