FULL INFORMATION ABOUT MOSFET TESTING | WITH A MULTIMETER |#laptop #motherboardrepair #dell
You must have seen the video of my Dell, okay, so in that case, there was exponential fall down, so what I did was, first I changed the capacitor, even after that it did not work, I said, there is a problem in the switch, that is, in the MOSFET, after that, I directly completed it from the boat, that mother board is fine, LDS connector etc. I installed it, I picked up four Muffets from this side from the boat, it was three or five and put it there, okay, the boat properly. His problem of fall down got solved, now it became three five, now we have on one side, I have kept low fat of both and high fat of both, this is low fat of both of us, okay, there is a low switch and on this side I have kept high fat of both, okay if I show the number, then this number of both will be the same, this number of both will be the same, okay, today I will test and show you, if you understand, you do not have that much muscle, you do not have that much scoop, which is absolutely fresh. Pick up and change the entire set
of three or five, I would recommend the same but if you have to do this, then understand that one or two Maspets here and there are faulty, otherwise you have to find that Maspet and replace it with a single Maspet like this, then you can also do that, there is a chance of failure in it, so I never do it. The section I am reducing, understand it is a section of 1.05 volts. From there I put a mosfet because its current and voltage ting is the same, okay, it is closed for every mother board, it is the same, no, I would say it is closed, okay, so first let's clean all this, okay, I had to make this video with petrol, okay, how to set the mosfet, so if you know about the mosfet of mosfet, okay, both of them are low fat, okay, let me see a little about it, will I be able to show you or not? The model number is ok, will it come in the camera or not? One second, I take a look, it is very small, but its model number is not very clear, even a second, I cannot see it, 7100 most prolly ok, let's see it once, yes, no, no, not saved, 02 7702, let's take a look right now, yes, this is also 7702, okay, it is not visible due to a little flux, but you will not see it, okay, so we will first learn to check it.
Okay, so if you look a little carefully, you can zoom in a little bit, you are fine, but if you look a little carefully, our Mosfet has three pins. Actually, okay, see what one is, there is one side, drain, one side is source and one is our gate. Okay, if you have kept it upside down, then the gate has come to this pin instead of this pin. Because if you put it like this, then it is this pin and
if you put it opposite to this, then this pin is It will be okay, understand this pin, actually three pins are there in it, only okay, if everything else is connected, then take some knowledge about how to test it, right now I have these two low fat, low fat and high fat, even if I mix it here, I can still tell which one is low fat and which is high fat, I am telling the concept of that, just see it now, okay, so I don't have any problem in distinguishing. You will also not have it if you have proper knowledge, okay, you have to keep the multimeter in diode mode, okay see, it is in diode mode, okay, you have to see the multimeter completely, okay, the screen, yes and the MOSFET too, I move it a little to the side, this is high phat, this is low phat, low phat of both means three and five are low phat, okay, if I put its plus on the drain and I will keep its minus on the source, then the reading should come zero, that means open. It should remain open, it is open, if I twist it, red prop, I am giving it at the source now and ground prop, I am giving it at the drain, on this condition you will get the reading, see it is ok, 201 is coming, in which pin you will get 201, find out because one number pin, two number pin and three number pin, all three are the same pin. If you check from here, B will tell you okay. Ya see, from here this B is okay, it is a little difficult to keep it here. P is fine,
three pins remain connected, right now, everyone knows that the last one is the gate, what do we have to do from the side it is coming to us, okay, the reading of 200 is coming from that side, we have to open our plus, we will keep the minus here, or I am telling about the testing of these channels, P will be just opposite to the channel, so what will we do, we will touch the plus with the gate, like this, I touched the plus with the gate, after this, if I touch it, this B should be said, see this. When I went to the lower edge, I turned back again, I am doing it again, here the ground is connected, I again moved this ground, this ground is mine, this ground is mine, it is connected here and I touched this place, okay, you can't see it and do a little inside. Let's take it, okay now it is visible, this plus plus minus should also be visible to you, so this is yours, this is your minus or your plus, here I have kept the minus, where the reading comes, on the other side, first I will find this reading, after that I will touch the gate, again I will touch here, so see this, it was shorted but after that, it opened again, this circuit is bad, okay, now it is his brother, let's check him, okay, which one among the three and five? I don't know but I assume because of what was found in our case, exponential fall down was found in three out of five, we did not check it, most probably it is Pa's low fat, it is ok because five had a fault, due to which even after changing the capacitor, it was not made, because three's capacitor was bad, five had a bad part, hence you got both the cases in one board, which has happened to me for the first time, okay, it is the same process now. From here I will check, first open it and put it on drain and on minus source, then it should be shown as open, see it is showing open, now if I reverse, sorry, I will reverse, then this is plus, I will put plus on drain, here I will put [music], oh why is it showing open, it should not have shown open, right color, I am the one who is wrong, on this side, minus, I will give plus to the gate, neither is it right, it will not come from this side, it will be reverse. If you do this then it will come, see is this also 204, is it also 204, 205, no, it was 207, so see, it is the same diode, its internal diode, now if I keep it in its gate and touch it, then this b is continuously opening, brother, okay, I am doing this again, this is also opening, okay, okay, let's test both of them once, okay, I thought that an open means the shot is not happening, but this shot remains open. It is fine, so if I test it, then
see it is a high value. Most diode value is high, which means it is high fat. Okay, this identifies it. I put it on the gate, it remains short, you can see that it happens like this, most of the time it is still short, it will remain closed until I touch it like this. By touching the gate source, it
gets discharged. Muffet and comes to the first position. See, if I put it here, it comes to the first position. While checking the second one, the mutt gets discharged. Most of the current is 200, it should be around 500, let's see if there is discharge or not, 450 flux is applied, so there is a little bit of discharging issue, okay, 550 has arrived, now let's touch it at the gate, it is also short, so this MOSFET, both are correct, I am a little doubtful about this mosfet, it went to two plus, it opened, it slowly got charged up and got up and it ran away more quickly, it is okay. I put
it in the voltage and see if it has opened, then it is okay, then this MSP is actually bad, okay, what is it doing that is open, it means that there is no register between the drain and source, that means there is some resistance which is pulling it, which is its gate, due to this, if you open it, if you short it, then it will remain short even after a minute, see, I will short it first, okay, look at the high fat from here, I have shorted it, okay shorted it, this shot has come, okay I Let me show you once, see the shot has come with an Om, I am leaving it, now it is fine, it is open, I have kept it, okay see, it is open, okay, it is not discharged, that is why it is taking a little time to get discharged, the discharging process is slow, but this discharge is going fast, okay, and in this, out of the two you got, you can see one which is running very quickly, this is what I passed, this is running away, it is discharged, now let's see this, if I will test it, this test means, after this, this I gave charge on the gate, see this short, there is a little more current in it, but less in it, but both the values are the same, so the switching of both should be the same, due to this, the fault was coming, okay, and if I check this, it is fine, it will still tell, see, it is still open, only shot is remaining okay, see this, oh friend, it is okay, what does it mean that our two mosfet are high, it has low resistance between its source and gate, okay? Sorry, there is high resistance, let me make a little diagram and show you, okay, if there is any paper heart, clear paper is not available, so let's draw a little bit, okay see, I draw a little bit here, okay, let's draw the mosfet, okay, look at the internal diagram, it has to look like this, okay, it will have a mouth like this on one side, these two will be connected, this is okay, it happens like this, right, Mosfet, most of the time, okay, a little bit, this line. actually From here there is gapping, from here it is connected, so on the side where it is connected, it becomes source, this is drain and this is gate, okay what I am saying and here we have body diode which goes in reverse, okay like this on the top side, this is called reverse, it is called body diode, so now when from drain and source, you keep minus here, minus here, you keep minus negative, meaning minus prop and positive here, then what will you get. You will get diode drop. Okay, here I am showing what I did. Okay, let's move it a little higher so that you can see the diagram as well and I can show any sample. So, what I said
is that the upper part is your drain and the lower part is three pins connected together, that is the source. Now the minus is on its side. If I keep the minus probe on the drain side and the plus probe on the source side, then a diode value should come, which means one diode. Drop should be shown, look, this is the same dia drop you are seeing, 900, sorry , 492, okay, now if I put a plus on the gate, then what is this short, that is, this switch is turned on, so what did I do, here I kept the minus b only, this is the minus b, but from here I picked up the plus and put a little plus here, okay, meaning I put a plus charged, so what happened, it conducted from here to here, this is how a short path was formed, okay, that's it, but It can be opened, that means power, you see this line, if there is a register attached with it internally, then it can discharge its gate, that is, as long as the pulse remains high in the gate, it is fine, so I made it low, sorry, as long as it remains high, it will continue to conduct you, whenever the current passes through this register little by little, it will keep going to the ground, then it will become low, then it will open, okay , so this is actually logic, so our low fat was in it, which is internal. Which is this register, this register is a little less in value, meaning it is 1 Mega Ohm, okay, and in this, our most probable one is 100 Mega Ohm, okay, so it will discharge slowly, if we short it today, then tomorrow it can come to open condition, but this is happening instantly, but even instantly, our two low fat ones, we have this higher one, one of them is getting faster, meaning this register is internal, this is 1 Mega Ohm.
Now if I explain to you about PWA, the wave that comes in PWA means on off on, then when it has to be on, then it is on, but when it has to be off , then it is delaying in turning off, it is okay, it is turning off quickly, sorry, it is not delaying, it is turning off quickly, meaning look at this, when you will check like this, it is not high after this. It is getting low like this, okay, that means where such a flat line was supposed to come, for some time, that flat line has become very small and is falling, due to this, our PWA was not able to build properly, okay, one was in line, that was not the fault of your mosfet, that was the fault of your capacitor, but which line I did not check, that means one capacitor out of five in line, sorry, one mosfet was bad, the switch was bad, I am showing it once again, see this. Props here, I put it, I gave it a positive charge, see it is still short, shorted and opened again, I do positive charge, see how much time it is taking, ok, this is what happened, I was slipping my hand again and again and just checked it, ok, took this plus, gave a charge, ok, it got discharged, see again, I do this, yes, ok, for how long it remained connected, shot, but it is not connected and still what is this, now it has opened. Okay, what I had shorted was mostly this and this, let's take a look, are both open? Yes, both are open, okay, so because of this, you have to find out which of yours is getting opened quickly and yours is a bad Muffet, okay, you change it single handedly, okay, let me show you again, so this plus, this has disappeared, so this fat is bad and this plus, this has been put, this is an okay fat, okay , understand a little bit for you. Now I will get it confirmed. Both of them are same. Okay, see, I said this is a high fat number. I want to show. I don't know how much I will be able to do. I haven't even cleaned it. Flux
is still stuck in it. Okay, I will clean both of them with a little bit of flux with petrol. Okay, so you understand how to check. What will be the maximum of the time? What will be the maximum of the time? It will remain open, it will not be able to get shorted and as soon as it becomes short, it will open immediately. Okay, if you see such a case, then let's try to capture it in the camera a little. Okay, try to zoom in. My phone's camera is good, so let's try. Hey man, it looks like it has gone away. Just focus a little.
Okay, see how quickly it was visible. Okay, what is it? 1568 8 is okay, this is high fat, see, keep it. Hey man, look, this is also Chuck keys, both are high fat, okay, look at this. 1528 Both have the same high fret and go towards low fret, okay let's move you to this, look at the low fit, okay, one of them is bad, one is good, so I will reverse it, okay see what is this, it is visible, brother, a little bit, it is visible, it is visible, see, it is 7702 A. Focus once again [Music] Focus is happening but it is not visible very clearly [Music] This Here, okay, let's check it once. Hey man, it has hit my finger. How big does it seem?
How much have I zoomed in? Let's find out that there is something stuck on it. Okay, let's clean it once. Okay, I am cleaning it with petrol. I am just rubbing it a little bit. This will remove the flux on it. It is not visible from the key. It is looking very clear right now. Look, now the most probe will come in the camera, right? Let's focus a little. Focus is coming, see this
. Kind of coming off, it is clear right now from 2A, look like this, one second, look at this, 77 02a is fine, it is looking 100% clear, 7702A, both are low fat same, but how can the behavior of both be different, see, 7702 is looking absolutely 100% clear, so how can the behavior of both change on this condition, only from this you have to know whether the MOSFET is bad, I am again I zoom out, bring it up, okay, on that one frame, I can show the reading once again, there should not be any confusion because many people are thinking, a lot of copying etc. is happening in the video, okay see, again I am doing 207, this is what I have given charge on the gate, it has become open, okay, let's do this, 204 must, 204, this is good, okay, most probably, see, this is 203, I have given it, meaning the gate is charged, it should be more open. OK, this is opening more quickly, so let's check it once again, it is open now, look at the gate with the charge given , my hand is shaking a lot, OK, this is the charge given at the gate, look at this, now this is opening quickly, brother, what are you doing, brother, something is going wrong, okay, it's gone, okay, it's gone right, let's do it here, plus, it's not working, isn't it , it's opening quickly, isn't it, it's opening a little less quickly than this, okay, yes, plus, look, it's okay And this is your plus plus, this is closed, it is open, okay, so this is yours, it is bad, actually okay, I mark this mosfet is dead, because of this, your three Pa problem is coming, okay, I mark okay, rest of these three mosfet are okay, both are hot, one is low fat okay, you have to change it, then only change it, but in this condition, it is the same mosfet of 200 V, if not. If you get it then it will not pair with it and one of your frets will be short. As soon as the short occurs, 19 volts will enter the 3-5 line and the bow will be dead. I do not take ricks for this, but if you have the habit of taking ricks, then take it, it is not your problem, okay, there is no need to worry, so thank you for watching this video guys. You needed some knowledge and I also wanted to give it, it
is okay, you have to always remember it, okay, don't worry about this process. You will get a lot of help at the time of checking. Okay bye [music] bye thr [music] pi
2025-02-25 07:57
