HP x360 14-dy0520sa coming on but no picture - Cold coil and hot chip is WRONG! Check this first!

hello so we are back and this time we have a nice laptop to repair H Pentium gold HP okay let's see what the customer is saying the customer it's a computer shop charging and power light comes on when button is pressed but no sign of Life caps lock not responding while power on light is illuminated work done remove motherboard did a visual inspection replace R try check inductors with and mosfets with multimeter found a components near the processor with continuity to ground which I don't think is supposed to be connected to ground but I lock the skills to diagnose further so we know the laptop is coming on we know it's charging fine oh it's not coming on okay let me plug a charger we need a HP plug blue pin that's the one blue pin HP uh 19 yeah plug in the charger 20 milliamps 160 so the laptop it is charging yeah we have War INE light there 170 milliamps so either the battery is fully charged or is the pre-charge current okay let's press the power button pressing the power button and the laptop it is coming on but he's taking like what like 20 30 milliam one upamp if I power off yeah it is taking some power okay that's fine that's okay let's open the laptop and let's check inside okay so the laptop it's open good we have a nice motherboard good okay ra memory present so what's the problem let's unplug the button and let's check the laptop the laptop is taking 40 milliamp okay no 10 30 what why is taking 30 I mean it's too you know this is too much current okay let's check with the thermal camera I mean I will do expect for a gaming laptop to take this kind of standby current now he's taking nothing okay pressing the power button pressing the power button the laptop it is coming on it's taking like 50 milliamps insane I mean we have no voltage on this [Music] motherboard one amp okay taking one amp okay that's good but let me check just you know to have an idea so the CPU has voltage you can see yeah that's a CPU good wow there is something very very hot what is that this chip oh L I can't even touch it is is that hot you can't even touch it why this coil it will be that sh it will be that hot what is's doing huh he supplying a lot of amps let's see so the output of this coil is 1.2 volts the RAM memory how can get so hard with 1.2 volts the coil is not that hot but the chip you can't you can't touch it that that's how hot it is that chip so what's the catch how the chip can be hot but not the coil I mean the coil it's 30° and the chip you can't touch it so what's the catch h who this is hot so this is a mystery yeah basically what the chip is doing is switching the Quil you have no current uh request from the motherboard on this Quil the Quil has to be cold the chip has to be cold the coil is like how I said SL slightly warm slightly warm but the chip you can't touch it you can't touch that chip but the chip is doing the job that's the thing the chip is doing the job we have 1.2 volts here but just because he doing the job that doesn't mean it's normal yeah not with those switching power supply where where the efficiency it's over 95% so if the coil is slightly warm the chip has to be probably the same or even less so I'm not happy with that chip L that's crazy I mean it's mat hot but it's strange because it is providing 1.2 volts okay let's have a look there let's see what we have there you know what I never seen this chip never ever never no never seen this chip so he's taking power from the main power l l 5416 let me see maybe I can find a data sheet okay I can't find anything about this chip I can fin to buy the chip but I can't find any info I believe this chip is supplying more power supply so check here here we have 5 volts yeah here we have 3.3 you can see good here we have 0.2 so what is here because this is a big Power here so what is here why I have 0.2 volts so I believe one of the outputs of this ship is shter that's what I believe here we have nothing you see another question why here we have nothing 0.6 here we have 1.2 here we have 0.5 why here we have 0.5 so this is a power L this is another Power l M so what's the story 1.2 here okay probably this is the feedback but what is here 0.5 and what is here with 0.2 anyone knows no one good let's do something stupid I mean I should check for schematic let's do something stupid let's go with some voltage here here and it's taking like 400 milliamps that's crazy and here same so once again those are connected together probably not why you taking that much current no not connected together but we ground no sorry here here nothing and here we have like 40 ohms so I'm not happy with those uh Power LS yeah so what I'm going to do I'm going to come with a power supply like before but this time I will check with the termal camera if the chip is getting hot then the chip is gone but can be a shorted output somehow somehow so this one is taking 440 milliamps let's see so this one yeah and it's getting hot what h no idea what is getting hot but it's not a cheap wa is not a cheap 440 [Music] milliamps uh is not is not a cheap okay let's see the other Power Ra which is here and it's taking 440 milliamps what is this a shorted capacitor check there no way so actually what is shorted here it's a capacitor so one more time coming with current here check that is the capacitor right it's not the chip huh let's see I'm not convinced so here right here yeah let me come with alcohol coming with alcohol so what what what is getting hard the capacitor the or the chip what do you think but check thata the alcohol check therea the alcohol is start spinning around the capacitor you can see look you can see look it's around the capacitor de capacitor say hello to my little friend yeah no you know what let's remove the capacitor let's remove it this time only this [Music] time I told there something wrong with that ship but I didn't believe it so the capacitor is out good perfect perfect uh heat sink just to cool the board a little bit let's plug the charger switching to 19 volts uh we need more current yeah plug in the charger and I'm curious to see what power ra was that let's see so there we have no voltage okay let's press the power button so pressing the power button yeah on the laptop it is coming on so here we have 2.4 volts H we have 2.4 volts now compared with like 0 point something last time and the chip is not getting hot anymore ah H can we have some picture please huh I need my pizza come give me picture it was a shorter capacitor we have picture that's crazy we picture yeah that was the issue that was the issue lol it was a nice repair huh I mean it's like yeah 21 minutes and he's loading the windows plugging the battery of course we can plug the battery of course I was about I was about you know to swear it's it's some bios issue but those switching power supply they have very high efficiency yeah you cannot have like a cold coil and a hot chip that that doesn't work like that yeah so all this when you see on you know you see something strange I mean okay this is hard but the Quil is cold uh that doesn't necessarily mean the chip is dead but can be a shorted output like here I mean I I don't even know what is there like 2.7 volts probably some internal ldo or some who knows external capacitor from that chip is like 2.4 volts who you know what I mean that's not the idea the idea is I cannot come with the you know I have like 0 point something I came with the power supply you know with like what what was that like two volts and the capacitor was getting hot and I said if the chip is getting hot most likely the chip is dead okay everything is working fine I'm happy I helped this customer um I mean it was quite a lucky repair I mean if I didn't have the you know the intuition just okay let me check with the thermal camera probably I will miss that ship which was getting hot I mean you'll never think okay let me touch that chip and see if it's getting hot no yeah okay so I will say thank you for watching watching you know like subscribe if you like the video and uh probably see you on the next one right yeah I still have a lot of jobs here hey if you find my content being helpful don't forget you can support this channel by pressing the join button and you can get instantly access to our members only cool collection and uh Discord private channels for support with your repairs also you can have a look on our United Kingdom eBay where you can find some cool and unique products United States eBay store or our patreon page thank you

Channel: Electronics Repair School

Views: 18,837

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Id: 9pm9Cr54Euw

Length: 17min 12sec (1032 seconds)

Published: Mon Apr 29 2024