How to find a shorted mosfet - safe & fast, no thermal camera or multimeter
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- Опубликовано: 20 сен 2024
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I have been following you for a long time and you are a great teacher and have interesting videos. Please ignore the negative comments and be sure that most people think only the best about you. I learned a lot from you and I'm still learning and it means a lot to me to look at some of your work at least one day. Thank you for that and greetings from Germany 😊
Hi Sorin! Totally agree with your methods in this video. But I have important addition! Like with GPU, when you have several phases in parallel you cant point exactly which mosfet is shorted. But there is a way! If the power from your power supply going through dead mosfet its also going through its coil! So you can take multimeter and measure voltage across coils and find exactly which one is under load right now! See, very simple! No need for thermal camera and no need to push high current, even 0.1A is enough to detect short circuit this way.
Works best if you set the multimeter in the mV range
You mean that only at the coil of the dead mosfet you 'll measure voltage more than 0V?
Where should the power suppply be connected? At the power jack?
Could you Expalin a bit more?
@@dimitrismaster explain more please
@@laptopguy2230 The voltage might be low to read in the normal volt range.
@@pgsss6354 Yes, you will measure more than 0V on a coil connected to the dead mosfet. Power must be connected to the shorted circuit directly. If its 19V power rail you can connect to it.
've been following electronic channels for a long time, I haven't come across such an exciting course in a long time. You showed us a method that is far from modern tools. That's the old school rocks over the tool-mania. Thank you Professor.👏
This man is ablolutetely best in electronics repair.. A genious of epic proportions. I have followed him for years.
You did an amazing job Mr. Sorin.
I always use coils to detect the short circuit, without a thermal camera or voltage injector, because the coils can never be connected to the ground, and that method that you used can lead to the exact place where the shorted component exists not just the MOSFET but any component that can cause a short to the ground like a capacitor, diode or IC.
Note :
When you short the two coils Next to GPU to the ground the voltage drops to 0.1 volts because that's coils are connected to the same power rail (+VCC GFX), because generally the CPU and GPU can have two power channels or more, and all that channels are connected to the same power rail (+VCC_Core or +VCC_GFX).
Nicely done keep going.
Yes, if you have shorted main power you can put some very low load to it and check voltage across every coil to find exactly which one is under load right now. Easy way to find which component is shorted in that part of circuit. No need for thermal camera, no risk to burn anything.
@@Evhen_Velikiy Right👌
Its Amazing to see Electronics Repair Basics_ERB comment. By the i'm also a faithful follower of your channel. Electronics Repair Basics_ERB, Electronics Repair School and AdamantIT are the best you tube channels that have taught me alot in these repairs. So seeing you here really uplifts my spirit. I love the solidarity.
I’m a complete NOOB, so please bear with me. When you say: “coils are never connected to ground” is that the same thing as saying that, they are always connected, in series? Did I get that right? Please let me know. Thank you kindly
@@maxwarfield6699 You need to read the basics of how buck and boost converters work in order for you to understand what's going on as regards this topic. There, you will se yourself how these coils are connected per each case...It's not so easy to answer your question with a simple "yes" or "no"...
Thanks for another great lesson professor Sorin 😊
You're the man Sorin! You found what works for you and you share it with your members. You are very talented and have a big heart. Thank you for being you!
Hi, I am a beginner student of electronics and this video taught me very well. If you post such videos for beginners, we will learn more. It's great. Keep it up.
This is one of the most versed videos made for this matter, Sorin. Thank you! 🤗 Although probably the title should say “CC/CV power supply required”, it's fine. Excellently well explained.
Concerning what you say about a “short killer”, which is something you mention hearing somewhere (Discord), and that it “triggers” you because somehow you find people using it incorrectly (“blood boils” and “insane”, you say): I know this well, Sorin, I know. It has to do with mind programming, and these things which you find @#$% are actually triggering something in you, and you react. The trigger most likely has to do with a negative mind program which you need to give up from or transmute (with the assistance of a good mind reprogramming healer if you can't by yourself) or at the very least you must learn to disable the trigger in you, so it no longer triggers you or it stops having a negative effect on you. I know this well, Sorin, and unless they are really willing to learn you cannot stop dumbass people from being dumbass; it's them who must change themselves.
Thanks again. 🤗
Thank you so much Sorin. I already do a lot of motherboard repairs. This has helped me find a short circuit on a rtx3090. ( which i could not work out due to no proper heat signal) agree with you. Those things that shall not be mentioned are a waste of money!
The other day I was watching one of your old videos about finding a short and you explained more or less the same thing and some of the videos are about 5 years old. This has been going on for too long and the connoisseurs will always try to be better than the master and I have seen it on so many platforms😅. Quote from NF "You cannot stop the world from complaining" and you cannot make them "better than factory"😂 ..We must remember it is part and parcel of the world going around at the speed of 30 kilometers per second in orbit around our Sun😅 Thank you Sorin for this wonderful lesson.
Nice, sweet, and to the point! I’ve been following you for a while and I find your instructions very informative! Thank you for what you do!!!
The Genius Sorin. Love your methods ❤ This can be only from experience and a gifted mind for electronics
When I had just started watching the video I said to myself, "this is going to be interesting". So I made myself a cup of coffee and watched the rest. I was right it was interesting and informational. So now it has been saved and liked. Thanks Sorin for making this educational video.
Thank You for this video, one of the best ! I think it will refresh brain even for experienced in repair, sometimes need to think simply logical but our heads is full and brain tricking us to look more complicated
try to never let people trigger you. happens every day, keep the good thing going my friend, im learning from you. thanks
Thank you for showing ur skills very appreciated
I repaired a shorted mosfet using "a sorin style" now the problem was when the customer asked me what I had put..... Sorin fuse🤣🤣🤣 and it worked nonstop ...but am hoping to replace that mosfet after some time coz the customer was in a hurry
You can use an alternative option for finding shorted mosfet.
You can test every single mosfets existed on motherboard with diode test and you can just check the impedance between gate and source. And that's it and if one a mosfet which has a low impedance between gate and source , you will be 100 percent sure that the mosfet is shorted. I think this is the best and fastest way to find a shorted mosfet.
I agree. But you need a multimeter. This method is safer than to insert voltage for those that are relative new to this.
You cant be sure that mosfet is faulty every time you have a short. Thats why its not practical to test every time all of mosfets.
@@Evhen_Velikiyyeah i agree. In some cases if the resistance between gate and source of a mosfet is low but not completely zero , we can be suspected that the pwm ic which is related to the mosfet is faulty , but if this resistance is completely near to zero , we can be sure that the mosfet is definitely faulty.
@@Drottninggatan2017 exactly👌
@@armanesmaeily7087 What if you have DRMOS'es on board? You cant measure source-gate coz there is no pin outside for gates. Only way to find shorted DRMOS is to supply some safe voltage to the shorted circuit and measure voltage across power coils. When you find voltage on a coil than related mosfet/drmos is shorted.
Someone was looking for a short finder but instead found Sorin's short fuse :D hahaha love it, and great info on using the power supply.
Sorin, you are the real deal! Thanks for the great video!
Thank you for showing a simple, safe and practical method to locate shorted MOSFETs and capacitors using only a good power supply.
In several places in the video, you read the voltage as 'zero point zero nine', 'zero point zero five', 'zero point zero one', etc instead of saying 'zero point nine', 'zero point five' and 'zero point one'.
It will be nice if you can repost the video showing the corrections in text.
Absolutely right people wants easy ways without knowing that sometimes its not correct. Something that boils my blood when I see some people wanting to teach in some youtube channels but they don't have it right . They think they do but at the end with what you learned you know they are not right .
Very good video, it would have been even better had you also drawn a part of schematics and showed which point actually got shorted to the ground.
people in Sorin's league generally don't need schematics
I feel like I also need some sort of diagram to explain it. I don't think I'm stupid, I just understand better when there is a clear diagram of what's happening. :)
@@daffyduk77 people watching Sorin are not in his league.
@@pgsss6354 Don't generalise lol I'm just here for the entertainment 🙂
@@daffyduk77 ...but, some of them, think they are
I have learned so much from you.
Keep up the good work :)
Great video! Saving it for future use! Thank you!
Brilliant!! Super brilliant! Changing the 6Omhs to 0ohms to check which MOSFET is shorted!
i'm trying to repair a monitor power suply and your videos are realy helpful; i'm suspecting a 3055 mosfet short
thanks a lot, now you have a new subscriber
good luck
p.s.- your accent seems like romanian :)
Before taking the motherboard out, shouldn't we check the BIOS first?
@West Senkovec: Simple man? Of the "old school"? Please, West, can you do me the big favor of putting me on your list, because of course I belong to that "select group" too. First BIOS? lol... you're terrible (in Spanish they would say about you unbearable guy!😊) All the best. A brotherly greeting from Mexico.
Excellent solution. BTW Sorin you can forget about your morning coffees, it is more than enough if you mantra that "short finder" thing a few times and and it will rises up your blood pressure immediately, more than any caffeine. :D
Greetings from Malaysia Sorin, it's 1am here. I should sleep but your video is the priority here😂
Well, it's very true a short-killer is NOT necessary and you can always use a bench PSU for this kind of shortcircuit finding procedures.
But I think you're just over-reacting a little bit, because after all, short killers are in fact also some kind of power supplys.
Dumb ones, true! Switching instead of linear, also true! But in the end, also power supplys nevertheless...
In fact, I think people are buying those killers because they can range up to 20A or more, and they are waaay cheaper than a decent bench PSU with the same current ratings. Remember that video from the A&I shop, where you said you wish you had more amps?
I think what you are trying to say is that we better stay away from those devices that don't feature a current limit setup (like many dumb short-killers probably do).
So should we buy one? Well, of course not! But if you already have such a device, with adjustable voltage AND current limit, I see no blood-boiling reason not to use it...
I have always just learnt a lot from your videos and techniques. Don't bother about other people's comments
The first important Tool is the Brain and know what are you doing. Sorin you are a great asset to us . Thank you 👍
Very helpful! Thank you Sorin. Wish I saw this video earlier. Make more videos like this one
thank you very much for sharing your knowledge and greetings from El Salvador in Central America
Thank you Sorin!
I was reading 00.7 or 0.7 while you were saying 0.07, etc.
Same here.
I love the alcohol spraybottle technique. repaired my first mainboard that way.
I have to admit..... you're ....very smart men! Thank's Sorin!
excellent teacher ive learned a lot today
Thanks for the info Sorin.
You don't need thermal camera, alcohol, multimeter, or burnt fingers, just your brain and power supply.
Smarter than smart.
What's the use of "tool" if you don't know what are you doing, if you don't understand basic concepts. Sorin is damn right.
Hi Sorin. I am new to your channel. I am electrical/electronic engineer. Probably I'll start one day my channel as well. You are a legend by the way.
Excelente seus vídeos, estou aqui no Brasil aprendendo muito com eles.
I appreciate your work, I wish you a lot more to learn from you. Stay healthy.❤❤❤❤❤❤❤
One of the greatest videos I've ever seen
THE Best teacher Ever.
So what ppl cal u by names.u r doing a good job .. free education for all.. good job indeed. God bless u nd ur family.
I have a weird laptop issue where it will power on briefly and go off (shows screen briefly with logo). So fairly sure good CPU+GPU. Without memory it will stay on but no picture, with fan spin. I tried for several hours to locate the short, even with thermal camera it was not showing, with most IC's and temperatures around 30-50c. Voltage gets around the entire board with the memory out (19v, 5v, 3.3v) and the board powered on. I've been hesitant to try voltage injection to find this short. I'm going to try this method when I have time to try again. I have watched probably 3-4+ hours of your videos the last few days to get some ideas, this one shows the most promise! Thank you again for your amazing work!
Also, yes, there is a whole bank of caps shorted in parallel which makes this one hard to find.
*Sorin Best of the best!*
Thank you for sharing this technique. Watching from Perth western Australia.
Learned something every time
Thanks
Thanks Sorin this is a nice approach to find a shorted mosfet
Thank for new idea sir Sorin
phillipines here 😊
I couldn't agree more Sorin. short killer and other similar products are just gimmicks especially when you already have a capable piece of equipment in your DC power supply. it irks me when a certain RUclips repair shop shills multiple times per video that everything they use they also sell, I got so fed up of listening to him harp on about it that most of the time i watch his stuff on mute now.
Hi Sorin thank you very much for this video. I in the laboratory source Koraxxx 30V - 10A, I can limit the current or voltage but when it reaches that limit it is blocked and you have to be pressing to unlock, and I do not just see how to test the capacitor shorts, and I also observe that depending on the type of cables you use for its thickness can give one value or another.
what an idea sir ,i think knowledge is wisdom after your video, still i have to learn i think videos like this ,thank you so much sir
Recently found your channel. Love you already :) Thanks man.
Excelente video...Short Killer es usado con aparente éxito para levantar cortos en las pantallas LCD....
Simple and powerful example of how experience trumps toys - nice one
you never stop surprising us. WOW
Nice video, I'm from Brazil and I understated you very well , good job! Thanks for share.
Sorin you are absolutely great. I wish I can meet you one day.. U r legend .. Thank you for teaching us something new..
On most rails, you can do that with just a multimeter. Check resistance from the shorted rail to each suspected rail and whichever one has the lowest resistance is the problem. That doesn't let you find which mosfet is shorted on a 16 phase gpu, though. At least 5 will be in parallel.
When your method would be particularly helpful is with something like a 3090 where the core resistance is 0.1 ohms and you can't tell the difference on the multimeter. The core will naturally draw around 2 amps, so with the shorting method, it will draw more current and hopefully let you feel the heat on the shorted mosfet with your finger, or possibly allow the trace resistance to make a slight difference in current draw. That way when you short right at the shorted mosfet, it would draw more current than when you short at the other mosfet. That's just a guess, though.
For shorts that are still above 20 or 30 ohms and not the VRAM rail, it wouldn't work, because it is likely a slight short to ground and there isn't enough current to affect any readings at all.
what a handful 🙄
@@edwinjuma4404 what do you mean?
Sorin's brain makes clicking noises, must mean he is internally short circuiting.
Good Work - Thank you for the upload!
thank you. Very important lesson
"If you have a short killer or a short finder.... don't say it" lol :D hahahaha too funny thank you for the video
but without short on coil, you must have 10v on coil with the multimeter...
Anyway, you are a gentleman of electronics !
Excellent video and thank you for your time. Great insight as always
wtf , nobody dis respects Sorin , he is awesome and honest.
For those who ask how....lets suppose that he shorted. Fet for boost cirxuit..now the coil is between shorted fet and power supply.....if u short before the coil the short will be more direct......as he clevery apply0.1. Small voltage and half amp.....the smps has happit of sacrificing the volt to let amp going....and with very small voltage he creates tool that have high sensitivity to ohm slightest fluctuation ..the dc voltage of 0.1 have the eye of sauron to the skiiping of coil resistance and applying more direct short.....this smps feature called cc cv ....constatnt current constant volt
Sorry I had written in Ita. You are the best, I have learned more from you than from anyone else...! Am I mistaken or is this called the Kelvin method?
awesome metode sir
Thank a lot Mr Sorin
Very helpful sir thanks
thank you boss, this is my first time to comment. you my mentor in electronics
Great video! And also a good lesson for ohm law 🙂
This video i liked the most . Thanks a lot for the efforts.
Last time i fixed a dead PSU and i see sometimes that parts not always dead short or open line, sometimes there may be malfunctions due to leaks of current or low ohms in circuits that do not have any short circuits or open circuits.
--The capacitors may be leaking, in this case they should be replaced with their equivalents.
--There may be Cold Solder in the circuit structure and this is one of the most common problems I encounter. It is also invisible.
--There may be a problem with the Bridge diode on the ground floor. It may leak.
--Mosfet transistors at the input stage may have completed their life. If these have dropped below 450 ohms, they should be replaced.
Shottky diodes may have decreased ohm at the -12v level..
--12v IC Controller in this region may be faulty.
TL431 transistors in the 12v stage may be faulty.
--The Zener diode ohm transitions to the IC controller may be more or less than the default.
I can count many more like this... dont always try to find dead short, it can be partial or lower ohm.
TL431 is not a transistor.
He was just talking about shorted mosfet in a computer mainboard which they were designed with similar way and happened very commonly.
Hi sorin thank you so much very informative and helpfull for me
Супер ❤
Спасибо. Лайк Вам 👍
That's right, he said in the end "use your brain".
Very good video 👍
Great Job! I will learn to use this method. Thank you.
great methode to find shorts! big thanks to the guy, who left this commend few days ago!^^
Awesome video. I learned so much as usual.
Ha ha, Now I see some use for one old powersupply I made in early -80s, max 30v and max 1A. Thank you Sorin the Wizzard
Thanks Sorin, you are my idol !!!
wow! just wow, the lesson is well understood, thank you very much.
Ypu are one of the best my dear Sorin ...God always bless you.
Sorin's magic!
Sei il migliore, ho imparato più da te che da chiunque altro...! Mi sbaglio o questo si chiama metodo Kelvin?
Awesome 👌 👏 Amazing explanation..many Thanks Sir..
Thanks for the work you giving . you are really Geneous
Hello I think like you, but some short killers has 20V 20A that's a good point to take in care.
Good stuff Sorin! Well done.
Awesome trick... Thank you sir..
you are awesome!!!!! I thoroughly enjoy your videos.
How do you know which side of the coil to short?
doesn't matter which side of the coil