Tv's - Diagnose and repair / power supply repair/replace/improvise

hello so we are back here same monday morning we just finished the hp with the wi-fi now let's start the tv the problem with the tv is i can do video only on the with the small tvs because obviously the big ones i i can't fix them on my desk yeah so we have a tv here and it's not working never heard about this brand bone full hd 21.5 inch model one b-1215 f dv i don't know looks like uh any tv 12 volts you can see the connector 12 volts so let's see what can be wrong here let's see what he's doing first here let's try i have the power supply and the removal let's try and power up by the power supply because we can see actually if the current is going inside or not yeah 12 volts we can't see the voltage only the amps only see ground can use any ground plus is taking no power where is the power button nothing ground yeah if i connect the ground is getting shorter does mean the ground is connected plus and nothing has another button somewhere no so one more time plus now the plus is connected power you can't see me pressing power here i'm sorry was short power nothing yeah it's clicking but nothing let's have a look what can be wrong here many people they are using this kind of tvs on the car because it's 12 volts one loaded drivers you know like you know the rev cars vehicles rv rv recreational vehicle yeah and not only not only how hard can be this to be fixed what can be here we looks like we have a power supply problem no power supply but actually my 12 volts are not getting on the board can be a fuse yeah it can be can be but it's stupid you know to put a fuse and put the fuse inside of the tv you know how can i know if it's diffused if it's no outside to access the fuse from outside it's kind of stupid you know on the old electronics they always put the fuse outside but now everything is inside and actually normal people they cannot access the fuse and replace the fuse this kind of stupid thinking you know they they took this from people they took this no like anyone like that doesn't have any knowledge you know but they can check a few you know just take the fuse look on the light see if he's burned or not busy okay we have few more screws so okay we have two more screws here actually everything in these days here they are trying to make the things like more complicated like let's get a phone let's let's get the iphone yeah so replacing a charging port it's a specialized job you know it becomes it became something you know it's a charging board you know that that's sick you know you have five volts there only plus and minus and you make a big thing from a you know a simple it's a charging port like on this one it's a fuse you know just put a fuse outside okay let's try and open this here plastic clips i probably can't see sorry okay and if we get open like that i'll try to get the screen out first we do the screen okay so we have a board the charging port looks sold around the place let's take the board out okay does the board that's the charging board and we do have a fuse you see that thing hit there yeah this one you see that black thing that's a fuse they cover the fuse on plastic i'll check the fuse for fuse first yeah multimeter there is no multimeter now sorry diode mode and the fuse is burned you can see it's nothing there should be like that yeah check the fuse is burn now one one problem before replacing the fuse the question is why the fuse is burned yes there are the fuse pins from there there what i will do i'll come with 12 volts after the fuse here ground so this is the input of the fuse here and obviously it's nothing and this is the output output of the fuse here output of the fuse short and the short it's not short anymore okay that's sick it was short it's not anymore how this is okay it's a burning smell but i can't see anything let's switch under the microscope and check together it's a burning like like semiconductor burn like a diode like a transistor like a chip something like that and shown should be something around the power supply hopefully it's not that cheap uh hopefully i'm so stupid you i i should try with less away less arms because now whatever was burned got burned completely yeah that was stupid what i just did because i lost any chance to find a problem like quickly oh it's still short okay i'll lower the amps yeah it's a nice 1.4 amps and something should get hot [Laughter] let me just uh i need the ground this now this yeah the usb port it's a good ground i can't see sorry and we have a short here 1.4 amps let's see what is getting hurt it's not the chip that's good but still smelling i swear it's a transistor this smell smoke no smoke transistor or diode is smoke i've seen smoke diode that's a diode smell after refusing after a few ah no don't tell me it's a chip ah i just burned my finger it is a cheap yeah let's have a look together most likely a power supply uh this one i was wrong i was thinking it's a diet it's not yeah that one ad 0 qg i don't know what's that sorry you can see okay let's use some petrol probably this is a power supply because it's connected to 12 volts and has a coil next to it yeah that's the one let me bring this on focus okay what we are doing now let's put the 12 volts i look at the chief it's everything got evaporated yeah one more time yeah let's come with 12 volts 12 volts fire you see so that's the problem that cheap and you'll say no sorry this is simple man it's wow you're so lucky it's just a chip now this this is actually this is the worst case because you have no idea what chip is adqg you have no idea what chip is [Music] and yeah you have to fix it but you can't charge too much because it's a small tv 20 inch tv so what we can do to fix this um okay the first step is to find out what power supply is this yeah that's the first step do you think the output is shorted and that's the reason why the chip is uh way the chip is is getting hot probably not let's take the multimeter yeah and let's find out together what that chip is doing so this ship is driving this coil here yes zero okay the output of this coil let's see have anything to do with this diode yeah is going to this diode have anything to do with the ground yeah it's shorter ground so the output of this chip is short to ground shorter to ground so i was nearly you know to swear that ship is gone i'm not sure now if it's gone or not so this chip is driving by that pin yeah so it is driving here maybe maybe the chip is gone yeah maybe so maybe the 12 volt is coming from the oh i'm not sure i have no idea now the query is connected to this pin here don't know if the 12 volt is coming from the other side of the coil or is coming from the different pin on the chip if i check this diode i'm sure it's shorted from some reason a t-shirt nearly short so what's going on here which is shorter the diode the chip another thing from the 12 volts power rail i don't know well you know what although probably the cheapest one looks like it's exploded i'll take out the chip and i'll check again yeah or i shall take out the coil but it's more easy to take out the chip more easy yeah let's say 400 yeah 400 degrees tweezer i need a tweezer found it okay the chip is out just be careful on the cheap position here that's the cheap position let's put the chip safe and let's see now what kind of short do we have ground yes i'm connected the ground let's see on this pin we still have short here so this is the coil yeah so actually we have a short on this side of the coil but you can't see so here we have a shirt here you can see on the mul no it's not short oh because that drive okay that pin is not driving the coil okay that's crazy okay so i've been wrong this spin is driving this is ground that's ground let's find out the plus so put the after the fuse i'll put one probe after the fuse because the fuse is burned now let's see which pin this one this is plus 12 the coil is to plus 12 is not okay that's crazy so the plus is coming here yeah the plus is coming here so the chip is burned and is closing the circuit here with this pin to the ground yeah so here is my shirt but i don't understand what the quail have to do here probably nothing but this is plus and plus is coming then this is plus this is ground what about the coil where the coil has to go let's see here nothing here nothing nothing here nothing nothing so that ship just was shorted or shorting everything the coil had nothing have nothing to do or maybe it was here nothing let's try like that yeah so that that coil is just uh it's just because it's here i have different driver probably this shoe from here is the driver of that coil you see they shave this one probably these two i don't know let's check this diode but the dial is still shorter this diode so that's the thing you have to understand the schematic before before jumping on some conclusion this pin is going somewhere you know i'm curious about this pin what this pin is doing where is going okay oh no no the other one is ground this is not ground probably this let's show you the coil yeah this is going to the coil yeah so the sec this pin is going to the coil this is ground and this is plus and the cheapest man to switch this pin to switch the ground because to the plus and ground because this is a switching power supply probably okay so if the coil is connected here yeah here connected the other side of the coil is the output yeah the other side of the coil is the output and actually the outputs are on these capacitors and the output is not short at the ground yeah it's not it's not yeah so okay that chip is dead but what power supply is this that's my question it's going to this one let's see where it's going because we have to find the voltage so we we found the actually the chip is dead the output is not shorted we have to find what value has that power supply what kind of voltage it's outputting so that's the output let's see where it's going here we have near we have a capacitor for 70 micro 16 volts actually is the beeping multimeter is more easy when you hear the beep this is going it's going here this is a voltage regulator this and this okay where is going more let's see on the main we should have a main 12 volts 12 volts we have i can't see on this board i have a saying 12 volts let's check after the fuse is not so probably from this output no from this no so from where i have 12 of the from the diode output now from this transistor or mosfet or whatever it is no okay we do have some five i hold vcc here okay let's let's check here you have any connection nothing nothing okay here here we have no nothing nothing level here nothing okay so it's not it's not going here for what these voltages use let's see screens can be 3.3 volts power supply can be is not okay five volts let's see five volts with the usb port usb port no but which is the 5 volts power supply of the usb huh because i will be glad to know let's see we have some test point 12 volts 3.35 volts okay let's see this one so five yeah and it's going to five this is a five volts power supply from the simple reason yeah yeah yeah yes so here you have some test points uh this one 5 volts vcc 3.3 is that jumper from the other side this jumper which is connected to five yeah this one is connected to five five volts and is beeping with my coil yeah so that's a five volts power supply that's we cleared that yeah we need a five volts regulator let's see how much power is taking on five volts uh and probably from the five is making 3.3 and so on yeah ground plus and the 5 volts is taking like 20 milliamps let's press the power button and we have red light look there you can see here here is red light power obviously nothing happened because we don't have 12 volts okay what i will do what i'll try yeah i'll try a trick because that chip is going anyway i'll try a trick if i have that if i have a chip need a 5 volts regulator remember i had before some small 5 volts chips regulators probably are not here anymore [Music] no i'm not sick give me a second okay let me have a look on the one we have some tv boards here let's see what we can find this is a tv board any chance i can find a chip like that probably not probably not what's this okay let's find when your five was regulated that's what we need so i found a chip here if i will have like a seven eight zero five i'll use it right now i have now this is uh we can't use this okay about this no okay what we can do in this case i do have some toys to play so that ship is normally how can i find it oh that's something else looks the same base not okay we do have some toy here i really recommend to anyone who wants to like modify the things this is cheap this is around 2.5 or 3 pounds on ebay yes proper chip this this circuit is based on the lm2596 yeah dc to dc buck uh converter adjustable yeah so actually this one it's a switching power supply yeah who can supply any voltage and i think can supply around two three amps something like that it's proper nice i haven't opened this one i will open now but you can use it and you can modify anything yeah like you don't have you have a non-working power supply like i don't know on the laptop on a tv or whatever you have it's so simple yeah output yeah you can see output input and that's all and you adjust the voltage what do you want more you know this is a simple thing okay so let's use this one and also it's simple simple it's it's it's a switching power supply nothing can go wrong here yeah and it's cheap like three i don't think it's three point i think i pay like 2.5 yeah 2.5 pounds for this kind of or you can buy even the chip even less of of two pound so what do we need now we need some wires and i swear i have no wires here and we can yeah we can do it it's monday i'm kind of lazy today because it's one day obviously yeah so i think the the ground is the same yeah let's check input and output output minus input minus yeah so we need only three wires actually yeah and i found three wires and because it's a stretching power supply actually it's it's extremely efficient so it will be no hit adriana is arguing with some customer on the phone that's sick that's it that's crazy i will tell you once again the customer one of the colleagues is working sunday okay let's see many times yeah it's iphone 7. we replace the screen here and he come back obviously with no receipt we fix it i fix it here it's warranty it's no sound and then i'll open the phone check and um it's not work on the board you know it's and they we called back and then i called back and said look it's uh what what kind of warranty you know is we didn't work on this one oh yeah we replace the screen and you give me three months warranty yeah but that's quite quite a different story you know yeah customer funny when you give them warranty they think they have warranty for everything you know uh you fix it should be a warranty yeah we fix the screen we have even people buying phones from here they drop the phone they crack the screen especially samsung phones and they come back say oh it's warranty and explain them you know it's it's it's damaged you drop it that's that's why the screen is cracked yeah but it's warranty you should fix it that's sick and you when you tell them you know it's you can't buy a phone go outside drop it and come back and tell me it's warranty and they start being funny like okay but what warranties cover you know these dishes are warranty the phone is broken you should fix it funny people funny people some people part this is like they are living on a and you know doesn't matter if i will drop it i have warranty no it's not like that it's not like that it's not like that okay so i will use i'll use the wires on this way yeah once i can so we have the output ground on the input maybe red will be input black is ground like usual and yellow is the output okay so let's find out the output and we can we have to adjust it before yeah 5 volts i'll switch to 12 volts 12 volts input is ground yeah yeah that's ground okay let me solder the input there's dust ground so it has ground and we have plus from the power supply which is the red i said is the red one hey 10 milliamps great let's check the output that's the output and we have the same we have a ground thing how can i keep all the wires this is plus okay i will keep like that this is the input output and now the power supply is set up on oh sorry that's dc it's it's diode sorry okay now the input and the output is 11 volts that's not good if i have same output let me adjust the the thingy unless you know same okay let's see now okay maybe she'll be on the other side here let's go on the other side i don't that thing is funny the adjustable thing same thing okay i don't think this is working the adjustable thing this one because i can't see any adjustment no should not be a load you know you don't need a load is a switching control power supply so we don't need a load but for some reason actually i don't think this is adjusting anything minus plus and now we don't even have light but that's good doesn't mean it's it's it's adjusting one second yeah that's input yeah oh yeah it is adjusting you see the i can see on the on the led yeah let's check we have ground let's see the output 3.3 you can see the output the voltmeter that's good yeah one second oh one second give me a second okay let's solder the wires yeah there's no point too we cannot use the power supply after yeah don't worry let's see so what do we have here yeah we have that shape sphere that she plays let's solder the wires and we are good and the thing is you can use this kind of modification or anything to replace like a power supply which you can't fix it yeah so we have ground here ground like you have grown from anywhere not only from here you know what there's no space here i'll use the ground from there yeah this is ground that's ground here the yellow one is output is here okay that's output and the input is 12 volts which should be here i set the third pin i probably can't see sorry i'll show you after here once i give you a second and plus it's on that capacitor which you can't see it i can't see it no one can see it because it's here that's 12 volts hey it's not a good position yeah i have to replace this wire okay let's do a good job here plus plus 12 here plus 12 volts what i will do now was good we really need to adjust that 5 volts power supply 12 that's good we have 12 the output here let's check the output i have ground here a screwdriver let me switch sorry and output and the output on this moment oh the ground is not connected it is now and output is 1.4 let's adjust this power supply up 4.5 5 volts you can adjust it like precisely five volts that should be fine yeah four point nine nine seven yeah you can see there but that's fine that's okay that's all that's all let's check if it's working thank you okay a few spheres it's not stupid it's not supposed to be that long this job looks like you know just to just to see how we can what we can use you know on a situation like that when you don't have the chip yeah and i'm sure if i look on it on google probably i'll not find that chip a nice two amp spheres okay that's all how the board was here yeah i will easily the board after here eventually you can use some hot glue to fix the board there let's connect the screen yeah screen and we have this connector and we have this connector which i do remember i think the connector was here one second okay and now we need 12 volts or we need the charger let's use the main charge area so okay so that's the customer charger and power we have red light we have blue light i press the power button and we have a picture yeah okay you can see of course everything is working fine yeah like changing the things here the channels power off here we can power off uh yeah now it's off yeah you can power on again yes on again yeah so everything is working fine i will not keep you because this is already long like one hour but that's the way how you manage to carry on you know doesn't matter that's not an excuse you don't have that part that's not the excuse you just carry on find the problem you find what power supply is there what is supposed to do and you just you just carry on with the repair because obviously it's easy to say i don't have the part i don't have the schematic you understand what i mean yeah okay thank you for watching like and subscribe if you like the video i'll put all back together i will uh isolate the board i'll put the board somewhere yeah i'll finish the job but was just an idea i could carry on if when you don't have don't have the part yeah so see you later yeah bye

Channel: Electronics Repair School

Views: 109,896

Keywords: tv repair tutorial, tv repair guide, tv repair without schematic, tv power supply repair

Id: FJxJ267j_9Y

Length: 60min 37sec (3637 seconds)

Published: Mon Mar 11 2019