Howto repair switch mode power supplies #4: Inductor in electronic circuits P2
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- Опубликовано: 8 сен 2024
- This is the follow-up video on the Switch Mode Power Supply repair series, where we continue on the t
opic of inductors in a circuit. Here we look at electromagnetic induction, magnetic saturation of the
inductor core, and we describe the full energy transformation cycle for an inductor, which is a simi
lar picture compared to a simple mechanical spring. For comparison, in the mechanical spring we conve
rt mechanical energy into elastic/deformation energy, and back into mechanical energy. In the inducto
r electric energy is being first converted into magnetic energy, next the magnetic energy will collap
se, and due to the change of the magnetic field around the inductor, this will induce an electric cur
rent. This phenomena is called electromagnetic induction.
By introducing the concept of magnetic saturation, where the electric current starts to grow very fas
t, we also mention the need for Pulse Width Modulation (PWM), where the switching FET transistor has
to turn on/off very fast, so that the inductor never reaches magnetic saturation.
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Much respect and appreciation from Kenya for the time, dedication and patience you have put in this wonderful series to impart this invaluable knowledge in such a simplistic and holistic way!!!
Not gonna lie, this channel is YT gold.
Content and speed are excellent. Wish you were my instructor in college! Thanks for the great videos!!!!!
Thankyou so much for share your knowlledge, I have study electronics in my twenties, and i am very pleased with your way to teach.
This is much better than any leasson at the university
Finally someone who's very thorough on this topic and doesn't skip things. Thanks for your detailed explanations
Excellent Presentation of information W.r.t. SMPS and it's Components. The presentation pace is also perfect, listener who have bit electronics background perceive easily. Thanks for making these SMPS series video and sharing across. This what exactly I was looking for about SMPS.
15:00 the measured current ("what we can see") is not flowing in the opposite direction when the field is collapsing. The collapsing field induces a voltage in the opposite direction that slows down the current, but the current itself is always flowing in the same direction. The spring analogy works for the mechanical forces of a magnetic field in the air gap (reluctance) of a solenoid, as both (spring and reluctance) store potential energy. Other than that I like to think of an inductor as storing kinetic energy ... you "accelerate" the current and then it keeps moving like a moving mass until you slow it down.
these videos where a lot of work on your part thank you for doing them. I appreciate them !
All videos about SMPS basics are excellent. Understand how much effort you have put. You are the best teacher. Thank you sir.
You are indeed blessed with the ability to TEACH. : )
Clear, concise and great analogies. Thank you for taking the time and effort to share your knowledge.
This guy is freaking both articulate and a certified teacher and an outstanding engineer. God bless you Bro. You really made my day. I have been searching since 2014 to self study electronics. Your way is far more better of teaching since you touch the detail of the components exfounding more and answer to our questions. You gave me hope to learn electronics in my old age. I am a retired programmer who writes lengthy codes and can express the approach and developed lots of various types of systems and application. Hence that no program is identical and it depends on the skills of the programmer.That all teacher is the same. You are a great educator. If i am your atudent. there is boring class and everything is all about learning. i love you man.. keep it up..God bless. Greetings From Philippines and now based in USA.
I've been watching your SMPS videos every evening.
Thank you !They are a GREAT review . I'm seeing SMPS's more and more in electronic products these days.
I hope this weekend I will have time to produce more content for the SMPS series, so stay tuned for more.
Due to higher efficiency and lighter weight, SMPS have practically replaced traditional linear power supplies practically in every application (except audio amplifiers, where their switching noise it too high).
I will watch for more of your videos. Subscribed !
Actually, I've been seeing more SMPS based guitar and Bass amplifiers come in for repair like the MarkBass and Gallien-Krueger.
They're light weight and cheaper to manufacture, but difficult to repair.
Wow, SMPS in audiophile stuff? Now that is actually surprising to be honest. Namely, the switching noise is
just too much for my personal taste. The only way to use an SMPS in good audio equipment is, that one uses SMPS as a so-called pre-regulator, and the voltage is than being pumped through a traditional low-noise serial regulator, where the serial element need to dissipate less heat, since the SMPS have already pre-regulated the voltage. Even so, some 'golden-ears' still claim they hear the switching noise in the headphones...
Awesome explanations, love the series. I studied a lot of this stuff in uni in ee, but it can be hard to put all that stuff together. This has been very helpful to help form it all together again.
A very good attempt to teach Electronics in a way anyone who cares to learn can learn The comparison of spring to inductor was really good
Thanks for the comment. Some people actually complained that they totally disliked the comparison between a mechanical spring and an inductor, and they think that a capacitor would have been better represented by a spring, which is totally counterintuitive for me.
Perfect presentation of SMPS repair. Both speed and content are awesome. Please keep it up.
Perfect presentation, kudos from Nigeria 🇳🇬
Appreciate very much your teaching and explanation. Makes things plain to me, though it looks so complicated before your explanation.
Just wow, absolutely amazing explanantoin, perfect examples, perfect presentation, everything is just perfect
your presentation is super duper
Thanks for the positive comment!
Now I just have to stop being lazy and produce new videos...
This is a very good explanation of the function of an inductor.
Your tutorial 1234 r excellent.thanks for all videos.
superb explanation
Fantastic sir. With a little knowledge u r explanation is clear in educating even lay man.thanks .Continue the same way
Thanks for the feedback. I turned into a lazy slob, and since a month have not produced new videos. Based on all the positive replies, I should get them going again.
Excellent teaching
Thanks for watching and commenting. I am happy that you liked the content.
Excellent!! Thank you!!
Awesome explanation thanks
thank you boss ,your explanation is so superb
Excellent video series. I have learned a lot.
aslm
hi thank you god bless your whole family
You are doing a very good job at explaining, top man
Thanks for the feedback!
If you got time, go through the whole series, now I am producing and uploading new videos on this topic.
you are my god , and i am your prophet. talking and recommending to every one about your video :)) thanks.
Well done for taking the time to explain things as you do. Some people might find you are taking too much time but I understand the importance of not rushing basic concepts. Just one tip - I know it's spelt circuit but it's actually pronounced as if spelt 'sirkit'. Keep up the good work (from a former electronics engineer).
Very nice thanks dear..❤
Very Nice...
Great video. I could only suggest less electronics theory content. Usually, people that want to repair a switching power supply already have the basic electronic knowledge. People that do not have that knowledge are not likely attempting to repair switch mode supplies.
I said the same thing. Part 1 and 2 are good. Then he got off on teaching basic electronics in a video about repairing power supplies.
excellent instructor...
You took lot of effort. thanks buddy 👍
Thanks for the positive feedback ;)
Excellent video!
Very good video series. Thanks mate!
Köszike!
1. while your approach to the subject from basic principles is nice, it could perhaps be a little faster.2. There is a need for some correction too.a) The direction of the induced voltage (and therefore the current generated by it) will be same as the original current, when the battery is replaced by the short. Nature hates change, it loves inertia! So, when the battery is removed, the magnetic field tries to continue as long as it can and so it creates an induced voltage with a direction that will keep the current going, even without the battery. This means the direction of the induced voltage will clockwise in your circuit and NOT anti clockwise as you have shown.b) When describing the effect of moving a magnet near the open circuit coil, you spoke of induced current, whereas it should be induced voltage. There can be no current with the circuit open.These remarks are not meant to diminish in any way the value of your project, which is laudable and I am enjoying it, even though I have some background in Electrical Engineering.
You are completely right. Also the mechanical analog of an inductor is a mass (hence the inertial effect) and not a spring, which is actually the mechanical analog of a capacitor.
@@alejom.depuch831 Inductor is similar to a Flywheel resists a change in velocity. Capacitor is constant voltage Inductor is constant current,the two work together to smooth out the bed of nails impulses to make a flat dc output voltage.
Nature does not HATE change as you state.
Hate, is a human EMOTION.
Nature RESISTS change.
Your choice of words are POOR.
Using the correct language and terminology is CRITICAL, and I tell you that as an
Electronics and Electro-Mechanical Engineer.
I see some issue with our statement "when the battery is removed, the magnetic field tries to continue as long as it can and so it creates an induced voltage". In my understanding, the voltage is induced because of shrinking magnetic field around the inductor. If there is no change in the magnetic field, there is no voltage induced.
Dipankar, sorry, but I think you are wrong. The voltage induced in the inductor coil is due to the magnetic field collapsing back in on itself, and so the lines of magnetic force are "cutting" the conductor (coil) in the opposite direction, as they did when the inductor was energised, and the magnetic field was expending. So the voltage induced by the collapsing magnetic field is opposite to the original. Think about the diode placed across a relay coil which is switched by a transistor. It is there to "short out" or bypass the "back EMF" generated when the transistor switches off, and the magnetic field around the core of the relay coil collapses back in on itself. This causes a "back voltage" spike which would likely destroy the transistor the first time it switched off. If that voltage was the same direction as the original, the diode would have to be oriented the other way around, and would thus short out the coil in normal operation, and it would never pull in the relay.
very clear explanation.Thank you!
Thanks for the feedback. I try to simplify things in order to not have to talk about complicated equations and such. Sometimes things get oversimplified, but I think that is OK as long as one get the main message.
Good work.Till Now we'll explain.
Your videos are very useful but I have an important constructive critic to make: the mechanical analog of an inductor is a mass (hence the inertial effect) and not a spring, which is actually the mechanical analog of a capacitor. Think of it as a car which is going to oppose to the force you apply to move it but once it’s moving it will conserve the energy as inertia.
So, in your circuits, when you remove the battery and place a short circuit in its place, the current will continue flowing in the SAME direction. What gets reversed is the voltage across the inductor’s terminals, being that voltage (the counter-electromotive force or CEMF) the one responsible of making the current to CONTINUE flowing in the SAME DIRECTION.
Very helpful video,thank you!
You should be an instructor. my teacher's at trade school don't come close
to youe detailed explanations.Excellent analogy's. Do you take donations? Good job!
I like the way he says "seercueit" for a circuit. Phonetically it's "Sirkit".
Yeah, that was a *classic* in the old videos. However, slowly I learned that it has to be pronounced differently. In the newer videos most of the time I get it right ;)
I am enjoying your videos. I still have trouble envisioning what the purpose of each thing is, generally. I'm trying to order Mosfet
s now for my power board, and it's crazy difficult.
@@DonkeyLearningIT
@@liberalmike27For ordering FETs I found that the top-down approach is the fastest. Namely, you put in the desired maximum voltage, maximum current, nominal frequency, and you sort for ascending price. After this, you can look at the RDS-on values as well, but I would not put that in the main search criteria from the very beginning. Also, it depends for which application you are searching for FETs, since nowadays most FETs are made for switching, and very few of them are usable for audio applications.
Thanks!
I pretty much just have the number/letter codes written on them. But when I search it gives me 30 types. Obviously, I need to match physical specs, like "through-hole." They screw into aluminum heat-sinks.
I did manage to find one datasheet--even found the exact model but I don't know Chinese! When it comes to matching all of the specs is when I get lost. My guess is most of them will work, at least with the main top several measurements. I wish I had the numbers here, but the television is over at my mother's house, as is the rest. Maybe a video about the main specifications for replacement MOSFETs you need to focus on, and those that matter less would be good.
You'd think they would offer a replacement of similar value and make it clear, but I'm guessing that would require a fantastical amount of work on their end.
@@DonkeyLearningIT
Sir qweettttt!!! :-)
Inductors are mad , I pull one out of a pc mthrbrd and used it to kill the power charging noise on my mobile phone radio :D
At 16:00 you have the induced current going the wrong way (bottom left). The inductor "tries" to maintain the direction of the current not to reverse it.
That is because I am preparing the viewers for the explanation of the snubber circuit and freewheeling diode. Sometimes one need to go in small steps. First we were taught in school that the earth is a sphere. Later that it is not a sphere, but actually larger around the equator, and finally that it is not making a perfect circle around the sun...
In any case, the explanation could have been better, that is true. At the time I made the video, this seemed the easiest way to explain it.
Duh... what are you talking about ? This is clearly misleading !
The inductance does not deliver a reverse current on circuit opening, but a reverse voltage that is largely exceeding the voltage it was delivered. This is confusing, but the voltage flipping actually permits the current to stay continuous, it represents the coil shifting from a consuming component to a source.
The whole comparison with a spring only works with the saturation principle, a coil opposes as much to a current increase than a current drop.
Presenting false information as truth to your students is a reprehensible failing of an educational institution, and should be extirpated, not emulated. I'm not saying you can't or shouldn't use an oversimplification, but make it clear at the time that it is oversimplified. I know something about the subject, but I wanted to know more. Now I feel that I can't trust the information being presented, and it greatly reduces my enthusiasm for your content. I realize this sounds harsh, and I don't really mean it to be. There's a severe lack of real-world information on how electronics works, and how to troubleshoot and repair. I want to encourage you to keep growing as an educator, keep growing your channel, and keep raising the standard of free educational resources available to people.
I was going to point out that, too. Guys, this series is so awesome, there is a lot of work took into it. Yet you act very rude, G1vr1x, Tythagoras. Go and take your hate on people who deserve it.
Sir, my hat's off for providing a so great material like this! Thank you!
OMG again with the inductors. You beat that to death in the last video. Move on!
I like this kind of knowledge bringing movies
Nice one.
This video is intended to all newbie like me, so those electrical engineering who post comment on this video complaining how everything is being discuss, please just please shut up. I wonder how you end up with smps repair tutorial if your that good on you field. so please just hold yourself and stop complaining.
Well, some of the comments are rightfully stating that the physics is being oversimplified. However, even an oversimplified understanding is better than no clue at all. This is why I try to keep the content simple but still informative for a broad audience.
Hello Donkey. I like you pace and your style. One question regarding your spring/inductor analogy. Please, correct me if I'm wrong, but in the case of an inductor, isn't the highest resistance to current flow PRIOR TO SATURATION, while the spring achieves highest resistance to force AT & SUBSEQUENT TO "SATURATION" (full compression)?
@Don. So inductors function is to hold the current to get the volts that we need right. can you share more about this? thanks
Im on video 4 and still no repair info. Maybe change title, "How it works"
Every nice
Nice lesson sir tkq
please show how to test each component in detail.
After I am done with the general theory, I will definitely show practical repair as well. Repair will make a *lot more sense* after going through the basics. The only issue is that I am really busy, so I barely have time until winter to make videos.
Nice series, though the contents goes way beyond the scope of the title: "Repair of SMPS". This is a complete electricity course.
That is exactly the point. Without knowing the way how SMPS works and regulates via the feedback loop and PWM, it is almost impossible to debug these circuits. Of course, one can change capacitors, and hope to get lucky. In most videos there was no explanation of *why* people exchange the parts and to describe *which* things to take care of. Most hobbyists are stuck at the basic question of why...
I would not recommend an absolute beginner who has no clue about inductivity to start repairing SMPS. Serious hobbyists should have knowledge about coils and transformers. BTW, this is dangerous gear because of the high voltages involved. On the other hand, coils and transformers almost never fail. If they do fail (burn) this is easy to detect because of the nasty smell. I would not spend four full video episodes on inductance only, it just takes too long to keep the interest going.
People often try to "repair" things from which they got no idea at all, in spite that they should not be even thinking about opening them. It is a *classic*, that people find a blown mains fuse in an SMPS, and they will just replace the fuse... Needless to say, 99% of the time such "repair" will not end well.
Whenever I open up any stuff where line voltages are exposed, I explicitly state that this is dangerous. Even if someone knows what to take care of, accidents can still happen even with good professionals.
My interest is peaked.
@@DonkeyLearningIT I think you are having a problem accepting that you went completely down the proverbial 'rabbit hole' when it comes to inductors. You can still explain the basic way inductors affect an SMPS circuit in WAY less time.
Hi mr Donkey, how exactly would a saturated inductor destroy a FET? Can't you feed more current than the saturation through an inductor and just not see a bigger magnetization?
super
Thanks for the super good comment ;)
For the future lectures, you should compare the coil with the block of mass, the spring with capacitor and the damper with the resistor. Otherwise you will be confusing your viewers.
There is a mistake. The current generated by the inductor will be in the same direction as it was before you removed the power.
Hi sr. I am from Cuba and i have downloaded the smps videos in order to study and repair switch power supply but when i try to play the videos throw an exception telling me about author rights so my question is: what can i do for watch the videos offline? I have not enough money to watch online
Are you sure the current goes the other way when you short circuit the energy source?
When it comes to autoinduction then yes, the current will be reverted. In fact, the current will be negligible, but instead there will be voltage spike, which need to be cut with a snubber circuit otherwise the switching element would be destroyed.
I found no easier way to explain this in a simple fashion, but to leave this oversimplified explanation. With time of course one can progress further, and explain to people what is going on, but gradual lectures are more important so that it is easy to follow.
Bibi Biskouaz, I cast a vote on your side.. It is a fundamental fact that the current flowing through an inductor cannot change instantaneously. Which means the current will keep flowing in the same direction. This is what I understand about the behavior of an inductor.
Are you sure you didn't just explain the capacitor?
A capacitor doesn't like when voltage changes and will use it's energy to sustain the voltage.
if u connect a battery to a capacitor the current will flow in one direction but when you replace the battery by a short the current will reverse!
A coil doesn't like when current changes and will use it's energy to sustain that current.
The current thru a coil cannot instantly change so when you replace the battery by a short the current will continue flowing in the same direction but the electric potential over the coil (voltage) will reverse!
A good video on coils : ruclips.net/video/NgwXkUt3XxQ/видео.html
i'm trying to troubleshoot a monitor power problem. it stay on for aprox 2 seconds and then it turns off the image and CCFLs. one of the secondary of the transformer has 12 volts. with multimeter it says 13 volts for 2 seconds and then between 12.73 and 12.78 volts
after this secondary there is a schottky diode. i desoldered the schottky diode and then put 12 volts in that rail with a regulated power suply. and it happens the same thing. the CCFLs and image stays on for 2 seconds and then turn off and the main LED starts blinking. if i push the on/off button twice, it stays on for another 2 seconds. this happens even putting 12volts with a regulated power supply. it shows around 1.73 amps of consumption when it's on.
there is a power problem? or it's something else? i'm guessing something else if I put external 12 volts and the problem stays.
btw, the capacitors are fine, and i don't have an oscilloscope
The symptoms you describe correspond most of the time with issues in the protection circuit, which was not yet covered in my series, only mentioned. In the case of CCFL monitors, when you are hit with this problem, almost 90% of the time the high-voltage driver circuit for the tubes is gone. Either the high voltage switching transformer is arcing/shorted, or the FET feeding the hight voltage transformer is shorted, or the FET is receiving the wrong PWM signal, turning the FET on way too long, where the trafo magnetics reaches saturation as I described in the video.
I would poke around in the high-voltage section, if I would be you, and figure out where the culprit is there.
Thanks
hello, great videos here, thanx-a-lot !! one 'thing' i still don't understand: is the DC-current flowing from - or + ?? at 1:37 you say from +, but i've also heard the opposite, which sounds more logical: that, due to an excess of (negative) electrones (which is what makes the negative pole negative) they actually flow from the - pole of a battery. could you please try to clarify this?
This kind of misunderstanding is caused by the fact, that when electricity was discovered by Galvani, people though that electric current flows from the + to the - terminal. Engineers have taken this notation, and this is what is called the direction of the *conventional current* flow. More than 100 years later physicists have found, that electricity is in fact the flow of negatively charged particles, what they called electrons, and in contrast to the conventional current, the *electron flow* is having exactly the opposite direction.
However, all engineering schools and books were using the conventional current flow, and there was no way to correct this "systematic mistake". This is why until this day in engineering the nomenclature is to use the traditional conventional current, and to mention that in fact the electron flow is opposite to this convention.
Great vids. FYI don't pronounce the "u" in circuit. Read it as Circut. Phonetically Searcut. Cheers
Thank's for detailed explanation, but i had some confuses from the part one of the videos, you said a alot about "current" and what made me more confusing is in video #4 at 08:20, you measure "current" in voltage (V) range of the multi-meter?
What is "current" definition in your videos? Is it voltage (V), amperage (A), power (Watt) or what? Please explain & thank you for the video series, it help me & confused me a lot...
If I have confused you, that is bad. The issue is, that having to talk later about auto-induction and snubber circuits kind of ties my hand to discuss vaguely about the material, and that is one source of confusion...
When I am referring to current, I am referring to amperage (A), and also using this as a way to describe "conventional direction" of where the electric current is considered to flow.
I do not want to confuse you even more, but actually the real current (i.e. the flow of electrons as charge carriers) is exactly the opposite compared to the way how the convention was made after electricity was invented. At those day people did not know about electrons, so they assumed that current flows from the + terminal to the -- terminal. This is why I have intentionally left this discussion completely out from the video, because it would get even *more confusing* ...
Donkey Learning IT
okay...
why you just don't said "the voltage will created when i move the magnet near the inductor" on this video at 08:20? why you said "current" when it should be voltage and not amperage? And more confusing proof you were showing the multi-meter on voltage probe when you explain "current".
Sorry for commenting like this, i want to learn a lot about this. But, every explanation i've read always the same when explaining current actually it's refer to voltage (V) not amperage (A).
Thank's for the explanation
"Current" is the flow of charge. "Voltage" is the pressure to move that charge against resistance. Voltage is the "potential" energy to do work and is often referred to as the "potential." (Correspondingly, current is the "kinetic" energy.) You can have voltage without current, which is what a battery and capacitor does. You can only have current flowing with zero volts in a superconductor, otherwise all current flow will have a corresponding voltage proportional to the resistance of the conductor. That is "Ohm's Law."
Voltage is measured in volts and current is measure in amperes. When a magnet is moved within a conductor coil, a "voltage" is induced in the conductor. If the path is not "open", this will produce a corresponding "current". The catch is that we often measure this "voltage" by measuring the "current" that it produces through some conductor, such as a meter, which always has some finite resistance.
So we have current, voltage and resistance. In any "normal" (non-superconducting) closed circuit, if we have voltage then we have current and visa versa. He's not wrong to talk of both. For any given fixed resistance, if the voltage goes up or down, the current will go up or down in direct proportion.
If this confuses you, then you need to seek out basic electronics tutorials. They usually all begin with Ohm's Law.
+
Donkey Learning IT
Not exactly... Current flows from negavie terminal to postive in reality...You can easly check it using amp meter. Connected to positive wire gives reading with minus...
Stupid question. At 9:00 when you are able to demonstrate current flow produced by the magnet through the coil, but with no external power source, why then can't a magnet be used as a power source for electronics?
A moving magnet next to a coil or a coil moving in a magnetic field is called a generator, and it is used in everyday life to generate power. This is what being used in all kind of generators from small dynamos to massive power plants.
@@DonkeyLearningIT My mistake was that the magnet has to be in motion to affect the current flow. So there obviously has to be a "mover", which in itself requires energy input. Thanks for clearing up my misconception.
Yes, that is exactly the idea, that energy need to be put into the system since either the magnet or the coil must move. This mechanical energy will be converted into electric power.
Electron flow from battery is negative to positive.
I hope you were jumping to the "repair" part, inductor explanation is not relevant, it's like you explain about all components, resistors, diode, transistors… I think I would be better to explain these things in a different series but in this series, I think these are irrelevant. Bytheway thanks for your time and amazing videos.
whats a serquid? and when do we learn how to repair?
I thought it was "sear quid". I guess that it's "4 sears".
3 video’s for coils/inductor is MUCH too long for me. Ok to speak about “change” or “accumulation”. That’s all.
Well, SMPS is all about the inductor. I am fully aware that by going faster I could make the channel get more views and more subscribers. However, luckily I do not need to make money with my channel, so I prefer to educate instead. People who understood inductors in a single episode can just skip the other videos.
Sorry Axel if a FREE course isn't perfect for you.
You can ask for your money back tho.
So it works like a capacitor so why dont use a capacitor?
No, an inductor works totally different than a capacitor. If the message what you took from the video was that this works like a capacitor, then I made a real bad presentation. Sorry for that...
@@DonkeyLearningIT sorry I didn't mean to offend you. I wished I had teachers as good as you. I just need to understand how it works.
i got a laser active a100 laserdisk gameconsole combo unit the powersupply has failed in it i lost 5v rail on dc side and the input at powerjack is shorted it took out the power mosfet the rectifier and the small tramsformer on the wall jack side i got all parts but the small transformer its labled L001 on the diagram link is here console5.com/wiki/File:SCH-2.png
also found ic202 was blown i tested and found no shorts to ground what do u think i should try first
There is no FET in the circuit you linked, they are all bipolar. Are you referring to the 2SC4275 (Q001???).
From your comment I could *not understand* what was blown, and what you have already replaced. Please go through the list, so I can help you out further. L001 is *not* a transformer. It is part of the power-input portion, and it is a common-mode choke.
Technically speaking, as long as it is not being really shorted, one could even just replace it with two fuses, but of course, this way the PSU will release *lots* of noise into your power grid. For short test it should be still fine.
On the figure you linked, there is no IC202, so I am wondering whether this part of the circuit is also available somewhere so I can look at it.
Donkey Learning IT basicly entire ac side is shorted the choke is burned and ic 202 if u look at the far right and trace back the (5v sw) output
Wow! Those chokes burn *very* rarely. Was the unit hit by lightning? This is what I suspect to be honest.
Remove L001 choke, and temporarily use two 2-3A fuses instead, where the two inductors were in the circuit. You do everything at your own risk! Before you do anything, I would first fix the power input section. Due to the type of damage you describe, I would replace C001, C002, C003, C004, C005 and also at the beginning I would remove TH001. TH001 is a metal-oxyde varistor (MOV), which goes to short if there is power-pulse going to it. The circuit should work temporarily without TH001, and also work temporarily without the choke, if you put in two fuses instead. Once you find the actual cause, of course, replace T001 and the choke as well. For the choke you can use almost any generic choke from an other switch-mode power supply. If you want to go cheap, you can also desolder these components, and measure them for short circuit, but *I would not* trust any of those components after the type of damage you describe.
Edited my comment, so see more details there...
Its good but you went so much in deep for inductors.....
Because inductors are the root of all good&evil in a switch mode PSU. After we understand the inductor, it is easy to understand why the PWM controller circuits are built in the way they are.
Donkey Learning IT
Much respect and appreciation for the time and dedication you put to impart this invaluable knowledge in such a simplistic way!!!
Sear quit => sir kit
Yeah, I know. In the meantime I am pronouncing it almost right, at least close enough ;) This is why it is good to have a YT channel with people who correct you, so you learn things together with them.
Too many charts and graphs, more live demonstrations please.
Well, I might be wrong but this is what a technician needs to know.
Regarding demonstration, the term is too broad. Thus, I am wondering more specifically what you have missed. If I have the time/resources, next time I will include some ideas you propose.
Furthermore, after I go through the theory part, I will rename all these videos, since they are indeed dry theory, I agree with you. Still, this theory is necessary to repair SMPS and know what need to be done and why.
Well, in may sense Joseph is right. However, one *must* go through some painful learning and reading charts, only after this is makes *actual sense* to touch an SMPS, debug it, and repair it. In fact, in most cases the charts, specsheets and circuit diagrams are not even available for most SMPS what you will try to repair, so you need to be able to "read the circuit" right off the PCB. Without step-by-step explanation on the theory, one cannot follow a modern SMPS even with a circuit diagram in hand...
You explain the subject well and your charts are a big help; don't worry if some students find it too difficult.
Thanks for the feedback.
As I wrote above, I think as a repair technician or even as a hobbyist one has to understand some of these concepts, so for the time being I have no better idea but to continue with this style and hope that people understand more things after they watch it couple of times.
Again with the spring!?? Why do we need 10 minutes to explain the spring. Get on with it already. This is the 4th video and you haven't really started to discuss Switched mode power supplies. The title should be intro to electronics
while the first lessons have been very interesting and well explained focusing on few detailed topics, this one about inductor is too much long and boring. I think it has no much sense in a serie called ''how to repair smps''
The issue is, that inductors are the heart of an SMPS, so this is why one need to cover them in detail. I know that when one looks strictly only on repair it makes little sens, but in the 'grand scheme' of SMPS the inductor portion is very important.
from 17 min video , only 3 min is useful, other talk makes video so boring
Circuit pronounce as "cirkit" not " cikwit" 🤣🤣🤣
Looking back I am actually happy that I did not have the right pronunciation at the time. This way more people had fun watching the video ;)
your videos are cool but you are repeating the same things over and over... go ahead to the point.
Its not a circwid its a circuit pronounced circ-it
Here comes the unavoidable pedant.
seerquit
Your username is my *dreamcar*.
How can one even register awesome usernames like this?
@@DonkeyLearningIT register it in 1999 :)