To learn more about electronics in a different and very effective way, and at the same time support this channel, go to Mr Carlson's Patreon page, click here: www.patreon.com/MrCarlsonsLab
hi, i like the switch mode powersupply videos, i was wondering if you could do a series, form the crappyest basic of a usb charger to adding protection, current reg, and other stuff.
Hi sir , can I know why the output voltage of the the SMPS Is high, it is not desired value. Example if desired value is 35 V , but it is coming 60V , what is problem in these SMPS
1. Этот модуль действующий. 2. Этот модуль движется. 3. Автор управляет этим модулем. 4. Гравитация подозрительно мала. 5. Скафандр почти не мешает записывать это видео 6. Название видео: "Монтаж smd компонентов в работающем оборудовании движущегося лунного модуля в открытом космосе паяльником Tesla, работающим на батарее Tesla, любезно предоставленном нам корпорацией Tesla. 7. Луна на самом деле не жёлтая, а красная. И летел этот модуль 300 дней. Наверное, это очень медленный модуль. 8. Борода делает ваш Скафандр теплее и уютнее.
My lunar lander did not take off.....Commonly called a divorce, as I lost my electronics shop in 2007 Well now it's 2022, and as iam single and starting over (in electronics that is) 👍 I know, sad.
Never seen anything like it. His first observation is the visual inspection with emphasis on build quality and quality components. Then the design engineering layout of the board. How he can identify immediately each subsystem and it's component and it's function. Then drawing the circuit and explaining the fundamentals from his intellectual mindset He was born to be a great teacher in electronics/electronic technology. Very few can explain or repair down to the component level. Keep up the great work !!
"If it does not work we will make it work" I love the confidence you show on problems. This was a very education video Paul. I always learn things from you. Like PLL circuits SMPS is another one of my weaknesses. Your hands on teaching method really helps. Thanks for another great video. Buddy
The Radio Shop you too huh. it took awhile for me to get my head around phase lock loops. but now i just picture a dog chasing its tail. lol ...theres a guy in the Philippines who offers a course on smps circuits. but from what ive seen mr c does a better job of explaining them. peace from Oklahoma city.
Mr Carlson you are a reference of the very best on RUclips. I expanded all the collapsed fields and saved to PDF to get a pure jewel of your comments/observations and those from all the viewers that also wrote brilliant and important comments/observations. It is a 73 pages PDF that I will read again and again for years to come.
WOW, I'm just learning on my own from RUclips and books, on this sight with the explications you provide I can deal in my mind what to do and what not to do, in troubleshooting but I know I must be very careful to take my time a listen ,observe, and be patient, thank you young man for a better day in my life with your teachings. miguel
Yeah, adult learning industry has FAILED. It FAILED multiple times in my experience as well. The lecturers were all about themselves and they were repulsive, disgusting people to be around 😒 But that's why internet was created. So the whole world 🌎 could do the main teaching for those people who want to learn 🤔
GREAT job. At the plant, we used to just toss them. I have been a tech for 40 years now, 28 of them sitting on a bench repairing 2-way radios. Again, you are great at explaining and appreciate your videos.
This is normal for internet connections. You're obviously surrounded by city folk and city folk mostly think lying leads to no consequences. Australia has a whole country full of this type of people 🙄 A full on social disaster.
Jesus - I so much love your Lessons - done not only with profound knowledge but calmly and comprehensive as well. Still (in terms of amount of Subscribers) very underrated channel.
oh WOW.... what a lab... 11 seconds in and I had to pause the video to fathom in the amount of devices you have skilled over the time with your profession.
I can't say enough how well you are to explain complicated electronic devices with your easy to understand language and perfection, learning new things every times by watching about what was my specialty when I was younger.
Well done, Paul! Great explanations. In the most simplest of terms, It could be stated the SMPS is the modern and sophisticated version of the old vibrators that supplied HV to auto radios in the 40's & 50's. Keep up the great work.
Many thanks for your excellent tutorial. I was a TV technician 50 years ago, repairing tvs to component level. Then I moved up to Avionics tech job and later on to an aircraft engineer's job. I retired after 40 years without board level repairs. After retirement I find a pensioner's life extremely hard. I am refreshing my electronics knowledge to be able to repair TVs or Computers.Please keep up the good work. aftab ahmed. London
I'm hoping to see more repair videos. Gotta love your confidence you can identify and fix the issue -- power supplies always seem to die an early death.
Probably the best explanation I've seen on youtube of what the transistors are doing within a circuit. I feel my understanding has made a quantum leap forward. Many thanks and certainly justifies my joining your patreon course.
Actually this is the best educational SMPS video for me. I have watched lots of them, they just talk and reading descriptions which you can find in datasheets or some papers easily. They dont describe every part of circuit just keep goin" this is the SPMS and it turns voltage yada yada yada...."
You're a really great teacher. Wish you'd been around Carleton University when I took Electrical Engineering there. :) I got my first oscilloscope when I was a kid. It was a World War II era Triumph I found at a garage sale, and I used it to repair the 1950s-1980s TV sets I would get at the curb. Being that the Triumph had only a two prong plug, it wasn't grounded, and I used to connect the stupid thing with reckless abandon everywhere in a TV chassis. What's the damper tube signal look like in a 1971 Admiral 21" delta-gun color TV? Let's find out! Looking back and realizing that the whole chassis and body of that oscilloscope was now live with B+ Boost, I cannot believe I didn't fry myself. But, in my defense, I did realize even as a child that electricity was to be highly respected, always used the one-hand-only rule, and never touched the two units at once. I learned the hard way about oscilloscope commons when I got a 1970s-era Phillips scope - which had a third prong. I connected the ground lead, turned on the set I was working on, there was a loud hum, and instantly the lights went out in my bedroom. It took a while to get the smell of burnt scope probe wire out of my bedroom. Thankfully, no other damage was done. In the early 1980s, lots of houses in Ottawa were having their furnaces converted to natural gas. Family friends gave me an oil furnace ignition transformer, with no idea how crazy-dangerous that thing was in a ten-year-old's hands. In fact, they didn't know what it was, they thought it was a motor - which itself would have been dangerous enough. When I made a little arc with it and heard the power of it, I unplugged it, and it became a toy to be operated only in the back yard with the distance of the lawn mower's extension cord between me and it. That was my own instinct, not every child is going to have that respect. I think I've had about three unintentional electric shocks in my life, amazingly nothing serious. One of them helpfully made my first car run better when it told me that my spark plug leads were shot. Most people aren't so lucky. Parents need to be alert to their kids working on electronics, whether they're TV sets or microwave ovens or guitar amplifiers or switching power supplies. Brushing against the horizontal output tube's anode cap on that old Admiral could have killed me instantly. I was afraid of electricity - still am, as much as I love it - and that has kept me safe. By all means, don't stifle the kid's interest in electricity. Remember that electricity is billions of times stronger than gravity and the fundamental force of nature that is right now keeping you from falling to the center of the Earth.
I will tell you my story....when I was 7 years old, the TV technicians that came to fix my old Phillips TV used to test the high voltage tube with a screwdriver producing an arc that for me was magical...I remember the TV tube failures because I keep asking questions that I think we're probably would not understand at that time. Once I was by myself trying to emulate what those techs used to do. My knoledge at that time was too litlle. I thought that the conector that is plugged to the tube probably was faulty and when I unplugged there was a gas inside the tube and was scaping due to the fact that I just unplugged. Well I put my finger on the hole so the "gas" should be stopped. Thank god the 120 volts was not connected. I received the 12000 volts discharge ....I couldn't move my arm, I was totally paralized by 30 seconds. I really thought that was the end. ... Conclution...if you happen to have a kid with curiosity about electronics teach him/her the danger things about it....today I am a happy electrical engineer that loves to mess with anything...I don't hate old tvs...as a matter of fact I admire the tube designers.... Mr. Carlson love your videos...keep doing them.....regards....
I wish I had never found your channel. I find myself watching your video's to all hours of the night and falling asleep in my computer chair. Although I originally came here to see if I could troubleshoot myself why my PC's corsair digital SMPS (AX1500I) at times goes into an infinite reboot, unless I turn off PS for some time (assuming discharging caps) and then restarting. I find myself watching being mesmerized by your knowledge. Sure wish I never dropped out of EE classes 41 years ago.
I find electronics boring but what I do like is old technology. Watched one of Mr Carlson's videos and was impressed with his knowledge. So I watched another and another. Now I'm hooked. Nothing more satisfying then to watch someone who is extremely knowledgeable and good at what they do. His confidence that he'll fix whatever the problem is very impressive.
Hi Paul, Thank you so much for sharing. ...I have to say, that I find, the videos you make are more than excellent. Your tutorials, presented with your obvious and observable depth of knowledge, and delivered in such a calm and measured manner, makes watching them highly educational and thoroughly enjoyable. Thanks again.
I really enjoy the way you approach all of your repairs for us common folk not in" the know" can still grasp the fundamentals being applied in actual applications. Thank you for spending what I'm sure is very valuable time to put this together. Have you ever worked on high frequency Inverter GTAW (TIG) Welders? Would you ever be interested in showing how one is repaired if so.
well done and geared to someone like me with fair understanding needing refresher but have not toyed with some of this stuff in more than 15 years like they say """" if u don't use it u loose it """ am now at point in life i am hobbing in HHO GEN., power plant pulse and stabilizing power output from unstable supple v.. this gives me things 2 think on with other life experiences. ie: associate degree in computers & electronic, ham operator , service mechanic, hvacr tech, plumber , service tech n butcher in 3 packing houses, boiler tech . and "JACK OF ALL TRADES "BUT u no the rest. TY VERY GOOD
Awesome video. I like pausing when you show circuit diagrams and trying to figure out how it works, and then hearing your explanation afterwards. I will be checking out your Patreon courses, cheers.
Another great video. The isolation transformer discussion was super enlightening. Recently I used an oscilloscope on a 1956 Admiral phono push pull amp that uses a power transformer. Figured I didn't need isolation. With the scope connection to the speaker (backwards) it created a hum. Even with the power switch off. I located a capacitor between the line and chassis ground caused it when the non polarized plug is inserted in reverse. Looks like isolation is good no matter what type of equipment is being tested. Thanks again.
Thanks Mr. Carlson for your gift of knowledge. How can anybody give this gentleman a thumbs down. When I was young, I had to ride my bike for miles to the public library (L.A.,CA.) and take notes after doing an extensive search for the correct information so I could use it in my guitar amp designs. I know that sounds like a joke but I'm serious. Learn what you can!!!
A very informative video sir. I am so glad that you stress the safety side of working on SMPSs and the use of isolation transformers. If you're lucky, the blue flash and the bang just gets your attention. If you're not lucky..........................
I often find it useful to just inject low voltage DC from a bench supply, instead of running full mains AC, while diagnosing a SMPS. That way you can safely check the switching and probe around as much as you like without having to be really careful.
That's what I'm trying to do,and as you said the brownout will kick in but you'll see some pulses before that, otherwise you can deactivated the protection since some ICs have a pin for that, or you can try injecting all the outputs not just the standby 5v.
My boss didn't like me to fix things like power supplies, "it's a waste of money". I did anyway, bought Solas for most new projects, never had to fix one, they are bricks. Excellent video, as usual. Kudos, and thank you.
I have watched quite a few of your videos and I have learned alot from them. Even watched some that are over my head and still have learned from them. Thanks. I will continue watching.
The ONLY caution I would add to your Video is to NOT handle a Power Supply without FIRST discharging the CAPACITORS . ALWAYS assume they are charged. That was what we learned in the Navy... Just my $.02.
I must have missed this one ,just watched it and what a brilliant explanation,im quite new at this and if you cant understand something you tend to put it to one side watching this has put my brain into 2nd gear, regards from across the pond 👍🇬🇧
Seriously, the first 5 seconds of the video i thought this guy is going to tell us how electronic troubleshooting in outer space is fixed. Very nice and informative video.
Hes very nice to listen to . Ive literally never said that before . i have a hard time focusing on people when they talk or explain things but man every word has my attention
I keep watching your videos. Now i could actually follow this video. From what i learned so far from you and what i knew, this video served another great lesson. I'm pretty glad I found you. Your a teacher I can follow and learn from. I will headed to Patreon and support you. Its only right. I gain so much from your videos.
Ten thumbs up! Excellent tutorial for working on 'hot chassis' circuits, which most modern consumer products are today. Floating grounds are the most commonly overlooked detail by techs today. (Afterall, who religiously uses, ever seen or even owns isolation transformers anymore? Those dissappeared with all the TV repair shops long ago) If that power cord isn't a 3-prong or is missing the ground pin ... big red flag, it's probably a hot-chassis design that can kill whenever the cover(s) are removed. A quick check with a battery-powered meter for AC voltage between the wall plug ground and the stuff you're working, can make all the difference.
Awesome job on the basics of switch mode power supply operation! Just now came across all of your videos and thanks for taking the time to make them. I've been doing electronics repair my whole life and still learn something new every day.
Yourself and Alan W2AEW have both missed your calling as teachers. You have a gift for relaying information in the right quantity and the right sequence. It makes watching the video actually fun while teaching very effectively..
Very cool explanation of switch mode power supplies. I have been studying NPN & PNP FET's over the past 2 days so perfect timing. You just gained a new subscriber.
Hello Paul, thanks for you channel, it's very good. About 50 years ago I built a 20W + 20W Mullard amplifier with a great deal of help. I Googled it the other day, it came up with 'National Valve Museum' - Gawd that made me feel old. EL34's Ah. I won't go into details but I was lying underneath this beast when a wire dropped across my nose. It was 410V. I was holding the earthed chassis at the time. You are very wise to warn people. If I remember correctly I said "Golly Gosh", "Fancy That" and "**** the thing". Even though most of your projects are well out of my comfort zone I do enjoy watching a craftsman. So many 'presenters' on You Tube are - let's just say 'overpowering' . Wide open spaces surrounded by teeth springs to mind. You are a pleasure to listen to. I have taken up basic electronics as a hobby again. I'm in the throws of converting an old 120W Monacor line amp into a 40V - 6A power supply. It came from a pub, a pint of beer didn't do it any good. Most of the 'gubbins' are fine. I'm going to try the TIP35C's it has with an LM723 but I have 4 x 2N3055's on standby. I'm also fitting a 400W SMPS - variable A & V. I don't mind fan noise. All I have is a Fluke, old but serviceable. Your video on SMPS and Linear power supplies was very interesting. I made a Joule thief and a radio ham friend went absolutely apoplectic. I told him I was going to make a 100W one with a long aerial but wasn't quite sure where to attach it. He thought I was serious - OOPS! Thanks again for the videos they are very much appreciated.
21:35 "And you might even destroy yourself" Classic. I have been earthed. Sent to ground. The final fuse has gone away, it gives and gives, we could go all day ;)
Mr. Carlson's Lab looks like he is the commander of his electronic space lab command center. His commands on the subject will make any problems be afraid to crop up and flee.
I agree. I am especially interested, as a hobbyist with no formal training, on where you actually connect the probes when troubleshooting various components. Can you actually troubleshoot transistors with an oscilloscope? Where would you hook the probes?? Thanks
R Copo...... o-scopes are easy, its the spectrum /logic /network analyzers that’s tough, like looking at noise floors at -130db or beta gain of a transistor, when measuring the curve gets upsidown....yea buddy...and using the sig gens properly, its fun stuff....all good
Hi Carlson, I simply love your videos. You explain all the relevant details in a clear and cogent manner, provide lots of practical tips and provide us the knowledge and confidence to attempt troubleshooting our devices that have stopped working. I am an electronics hobbyist from Bangalore, India and I was thrilled when you said, "If it doesn't operate, we will make it operate, not a big deal". But when you supplied the power and the meter showed 24.01 V, I was disappointed. I expected the power supply to be in a non working condition and wanted you to diagnose the problem in your meticulous and systematic manner and do the needful to make it functional again. That way, there is a lot more scope for us to learn the art of troubleshooting. Thanks for your wonderful videos and eagerly looking forward to more of them.
THANK you for taking all that time to make this video. im the type that has to learn something every night before bed and im new to circuitry so this is amazing. keep up the great work
Really informed presenter here! Seems like a good opportunity to see if any true sign wave inverter explanation videos are posted to this channel.. The way I understand this circuit is that it's a pure square wave on the primary side out of the FET's. I'd love to see it taken one step further and understand how the bases are modulated in such a way to achieve "stepping" or better "true" sign waves. Thanks. And again, great video!
Best explanation for half bridge smps on youtube excelent work.And one thing to remind that you forgot to explain how te feedback works so it can stay regulated,but overall great work.
Great video Paul, i like the inclusion of the oscilloscope. I recently got my first scope but not brave enough to use it fully yet, forgive the newbe question but could or should i use the scope on the same isolation transformer as the device under test? my area of concern is being tied to ground and frying something?
Noel Nestor - yea that is exactly what I was wondering. Would one require a second isolation transformer to float the scope? Although the scope manufacturers won't agree with that ...I would be grateful for advice on this as well. Love all the videos Paul.
Just for clarification i am using a rigol 1054z, so i think my options are using differential probes but thats expensive, using a maths function or running directly from a battery pack, i have tryed a 48v battery and it works but alot of hassle charging batteries
You isolate the circuit under test. Besides frying the scope you can fry yourself if you do not use an isolation transformer. With an isolation transformer in place: if you accidentally contact the "hot" wire, you will pull it to ground. However, if you contact both the "hot" and "neutral" wires at the same time, you are setting up a short circuit. -By putting your scope on the isolation transformer, with the circuit under test, you lose protection for the scope.- The ground on the scope will possibly be floating, unless you tie it to neutral. -- I was originally going to say the short-circuit risk described above is still present, but I don't think it is common to tie neutral directly to ground in equipment: that happens at the breaker panel. The scope may need proper grounding for safety reasons (to make sure stray voltages are not induced onto the chassis).
I suppose where I am getting stuck is by using an isolation transformer (as I do for the device under test), am I not just introducing a path to ground by probing with the ground clip? I'm learning at the minute and want to keep as safe environment as possible for me first of all and the scope also.
Noel Nestor You are introducing a path to ground, but the isolation transformer isolates the circuit under test from it's normal ground. That way, the rest of the circuit under test can "float" relative to ground. You still have to be careful due to the large voltages present.
I'm coming to your channel late, Mr. Carlson. I wish I had discovered you sooner. I have troubleshot a couple of SMPS's and got lucky. Most of the time, I toss them and order a new one. It is nice to see how to troubleshoot them. :) Thanks for posting. :)
Just very well done and absolutely great to have people share knowledge like this. There is life on the internet. Thank You, I am with joy going through your videos. Great job. / Patrik, Sweden
the repair would follow a similar line BUT a lot of failures in comp supplies are dud caps (bulging tops) main cause of failure followed by complete blowup of choppers (not worth fixing) but do check the caps also the same on mother broads. many thousands of machines scrapped because of a bunch of cheap caps dying.
Konstantinos Nano should make power supply with u mechanical motor running gears for diffrent voltages a pma generator with all the voltages at the right rpm but charged from solar or wind to capacitors runnning 3 phase permanet magnets simple to fix with hardly having to know so much.
Awesome video. Simple and going slowly through whole build. The only thing that I would change is that when you are measuring, the camera could stay on the circuit and the some smaller screen on the measuring equipment or vice versa. (I did not have chance to watch rest of your videos when maybe you applied it already but for this video this is what I would love to see). I was looking long for just this simple step by step description on how the PSU is working. Thank you very much! It is now much more enjoyable to learn this stuff.
I spend every day repairing power supplies in high power professional audio equipment and whilst your video was informative it allows exposure to dangerous voltages. there's a much easier and safer way that doesn't want to kill you at the first slip. you'll need a lab power supply and a few links. Find out what your amps controller plus gate driver is then power up all the oscillator and drive circuits with the psu. a few bits of trickery are needed sometimes to convince the shut down pin to get the correct signals. simply put, the only time you need high voltages is to switch through the devices. once all gate signals are happy and there is zero crossover then get a second pus and shove maybe 30v into the bridge rectifier and make sure the devices are switching current though the windings, and of course measure the output of the secondary rectifier voltage as a functional relationship to the incoming voltage. no danger, simple and reliable
Isolation transformer DEFINTELY is good advice! I was replacing components on an SMPS and completely forgot to turn it off. Kept thinking: "God, I swear I feel a little tingle every time the solder touches the board. Must be my imagination." No, it wasn't. Turned it over and the LED was lit indicating it was powered up the entire time. Surprisingly, it survived having random components taken in and out of the circuit. Thankfully, the isolation transformer did its job.
Couldn't they have simply driven the MOSFETs directly from the IC and saved some transistors and a transformer? The only catch is that they'd have to use 2 inverter gates (or even a 4N25 opto-isolator) at the IC outputs to provide a brief logic-high pulse to the gates, since the IC provides a brief logic-low.
No, there is about a 160 volt difference between the two gates. The transformer is required for that IC. You can get different switch mode ICs that can directly drive the mosfets though.
Well, there's also the issue of primary-to-secondary isolation (ie. between the mains side and the low-voltage side). Yes, there are also PWM controllers that are intended for use on the primary side, but even those would need some sort of gate-driver ICs (if we're talking half-bridge designs).
I assumed this to be the case but I'm glad someone asked the question so that a knowledgeable person could provide the affirmation. Following along as a layman, I had the same question as Mr. Squires.
Good job for making this video. There are few people videos about SMPS, and most of them they are not explaining so good. Keep up the good work ! Thank you !
@@AN-kg4ei Quality import. So the transformer had the screws loose and one fell off. But easy fix. Works fine. Hard to mess up a switch, transformer, and outlet.
When I first opened up your vid I thought you were going to take us on a journey to the moon in Apollo ha. Seriously a brilliant explanation, I learned a lot if at least to leave well alone. The high voltage capacitors with charge left it them also pose a harmful risk of electrocution, perhaps worth a mention. A great lesson thank you.
To learn more about electronics in a different and very effective way, and at the same time support this channel, go to Mr Carlson's Patreon page, click here: www.patreon.com/MrCarlsonsLab
hi, i like the switch mode powersupply videos, i was wondering if you could do a series, form the crappyest basic of a usb charger to adding protection, current reg, and other stuff.
Can you tell me how will check electronic components
Hi sir , can I know why the output voltage of the the SMPS Is high, it is not desired value. Example if desired value is 35 V , but it is coming 60V , what is problem in these SMPS
Urmim
When you say “really bad things will happen”, excuse my ignorance but what exactly happens?
You know hes a pro when you see him sitting inside a 70's lunar lander!
No doubt!
I know my mechanic is a pro cause his desk is surrounded by car parts. 🚗 😀
Best comment ever!!!!
1. Этот модуль действующий.
2. Этот модуль движется.
3. Автор управляет этим модулем.
4. Гравитация подозрительно мала.
5. Скафандр почти не мешает записывать это видео
6. Название видео: "Монтаж smd компонентов в работающем оборудовании движущегося лунного модуля в открытом космосе паяльником Tesla, работающим на батарее Tesla, любезно предоставленном нам корпорацией Tesla.
7. Луна на самом деле не жёлтая, а красная. И летел этот модуль 300 дней. Наверное, это очень медленный модуль.
8. Борода делает ваш Скафандр теплее и уютнее.
My lunar lander did not take off.....Commonly called a divorce, as I lost my electronics shop in 2007 Well now it's 2022, and as iam single and starting over (in electronics that is) 👍 I know, sad.
Never seen anything like it. His first observation is the visual inspection with emphasis on build quality and quality components. Then the design engineering layout of the board. How he can identify immediately each subsystem and it's component and it's function. Then drawing the circuit and explaining the fundamentals from his intellectual mindset He was born to be a great teacher in electronics/electronic technology. Very few can explain or repair down to the component level. Keep up the great work !!
It's called experience.
He can identify the design and components because of his education and experience.
"If it does not work we will make it work" I love the confidence you show on problems. This was a very education video Paul. I always learn things from you. Like PLL circuits SMPS is another one of my weaknesses. Your hands on teaching method really helps. Thanks for another great video. Buddy
Thanks Buddy!
The Radio Shop you too huh. it took awhile for me to get my head around phase lock loops. but now i just picture a dog chasing its tail. lol ...theres a guy in the Philippines who offers a course on smps circuits. but from what ive seen mr c does a better job of explaining them. peace from Oklahoma city.
The Radio Shop aww
@@billybonewhacker who's that guy. Can you give me a link to his website?
@@billybonewhacker m
Mr Carlson you are a reference of the very best on RUclips.
I expanded all the collapsed fields and saved to PDF to get a pure jewel of your comments/observations and those from all the viewers that also wrote brilliant and important comments/observations.
It is a 73 pages PDF that I will read again and again for years to come.
How'd you do that?
You said it man.
Robert St-Lauent how did you do that? I mean the PDF files.
So you're surrounded by city folk...
WOW, I'm just learning on my own from RUclips and books, on this sight with the explications you provide I can deal in my mind what to do and what not to do, in troubleshooting but I know I must be very careful to take my time a listen ,observe, and be patient, thank you young man for a better day in my life with your teachings. miguel
Yeah, adult learning industry has FAILED.
It FAILED multiple times in my experience as well.
The lecturers were all about themselves and they were repulsive, disgusting people to be around 😒
But that's why internet was created.
So the whole world 🌎 could do the main teaching for those people who want to learn 🤔
GREAT job. At the plant, we used to just toss them. I have been a tech for 40 years now, 28 of them sitting on a bench repairing 2-way radios. Again, you are great at explaining and appreciate your videos.
I really appreciate the orderliness of your explanations. Very clear and precise and organized, just like electronics.
This is normal for internet connections.
You're obviously surrounded by city folk and city folk mostly think lying leads to no consequences.
Australia has a whole country full of this type of people 🙄
A full on social disaster.
Jesus - I so much love your Lessons - done not only with profound knowledge but calmly and comprehensive as well. Still (in terms of amount of Subscribers) very underrated channel.
oh WOW.... what a lab... 11 seconds in and I had to pause the video to fathom in the amount of devices you have skilled over the time with your profession.
I can't say enough how well you are to explain complicated electronic devices with your easy to understand language and perfection, learning new things every times by watching about what was my specialty when I was younger.
Well done, Paul! Great explanations. In the most simplest of terms, It could be stated the SMPS is the modern and sophisticated version of the old vibrators that supplied HV to auto radios in the 40's & 50's. Keep up the great work.
Many thanks for your excellent tutorial. I was a TV technician 50 years ago, repairing tvs to component level. Then I moved up to Avionics tech job and later on to an aircraft engineer's job. I retired after 40 years without board level repairs. After retirement I find a pensioner's life extremely hard. I am refreshing my electronics knowledge to be able to repair TVs or Computers.Please keep up the good work. aftab ahmed. London
I'm hoping to see more repair videos. Gotta love your confidence you can identify and fix the issue -- power supplies always seem to die an early death.
I came here....4 years later......to repair a similar Power Supply. Mission accomplished thanks to this video!
I swear I watch this Canadian equally for his understated enthusiasm and much for his obvious PhD. Chops. Carry On Sir.
Canadian, that's it!
I knew it was isolation.
Everyone else is full of lies.
On this entertainment, the components lie.
Probably the best explanation I've seen on youtube of what the transistors are doing within a circuit. I feel my understanding has made a quantum leap forward. Many thanks and certainly justifies my joining your patreon course.
Glad you enjoyed!
Your videos are incredible. The information you present and the quality of the videos is really second to none. Excellent stuff!
Thanks for your kind words!
Actually this is the best educational SMPS video for me. I have watched lots of them, they just talk and reading descriptions which you can find in datasheets or some papers easily. They dont describe every part of circuit just keep goin" this is the SPMS and it turns voltage yada yada yada...."
You're a really great teacher. Wish you'd been around Carleton University when I took Electrical Engineering there. :)
I got my first oscilloscope when I was a kid. It was a World War II era Triumph I found at a garage sale, and I used it to repair the 1950s-1980s TV sets I would get at the curb. Being that the Triumph had only a two prong plug, it wasn't grounded, and I used to connect the stupid thing with reckless abandon everywhere in a TV chassis. What's the damper tube signal look like in a 1971 Admiral 21" delta-gun color TV? Let's find out! Looking back and realizing that the whole chassis and body of that oscilloscope was now live with B+ Boost, I cannot believe I didn't fry myself. But, in my defense, I did realize even as a child that electricity was to be highly respected, always used the one-hand-only rule, and never touched the two units at once.
I learned the hard way about oscilloscope commons when I got a 1970s-era Phillips scope - which had a third prong. I connected the ground lead, turned on the set I was working on, there was a loud hum, and instantly the lights went out in my bedroom. It took a while to get the smell of burnt scope probe wire out of my bedroom. Thankfully, no other damage was done.
In the early 1980s, lots of houses in Ottawa were having their furnaces converted to natural gas. Family friends gave me an oil furnace ignition transformer, with no idea how crazy-dangerous that thing was in a ten-year-old's hands. In fact, they didn't know what it was, they thought it was a motor - which itself would have been dangerous enough. When I made a little arc with it and heard the power of it, I unplugged it, and it became a toy to be operated only in the back yard with the distance of the lawn mower's extension cord between me and it. That was my own instinct, not every child is going to have that respect.
I think I've had about three unintentional electric shocks in my life, amazingly nothing serious. One of them helpfully made my first car run better when it told me that my spark plug leads were shot. Most people aren't so lucky.
Parents need to be alert to their kids working on electronics, whether they're TV sets or microwave ovens or guitar amplifiers or switching power supplies. Brushing against the horizontal output tube's anode cap on that old Admiral could have killed me instantly. I was afraid of electricity - still am, as much as I love it - and that has kept me safe. By all means, don't stifle the kid's interest in electricity. Remember that electricity is billions of times stronger than gravity and the fundamental force of nature that is right now keeping you from falling to the center of the Earth.
I will tell you my story....when I was 7 years old, the TV technicians that came to fix my old Phillips TV used to test the high voltage tube with a screwdriver producing an arc that for me was magical...I remember the TV tube failures because I keep asking questions that I think we're probably would not understand at that time. Once I was by myself trying to emulate what those techs used to do. My knoledge at that time was too litlle. I thought that the conector that is plugged to the tube probably was faulty and when I unplugged there was a gas inside the tube and was scaping due to the fact that I just unplugged. Well I put my finger on the hole so the "gas" should be stopped. Thank god the 120 volts was not connected. I received the 12000 volts discharge ....I couldn't move my arm, I was totally paralized by 30 seconds. I really thought that was the end. ...
Conclution...if you happen to have a kid with curiosity about electronics teach him/her the danger things about it....today I am a happy electrical engineer that loves to mess with anything...I don't hate old tvs...as a matter of fact I admire the tube designers....
Mr. Carlson love your videos...keep doing them.....regards....
I wish I had never found your channel. I find myself watching your video's to all hours of the night and falling asleep in my computer chair. Although I originally came here to see if I could troubleshoot myself why my PC's corsair digital SMPS (AX1500I) at times goes into an infinite reboot, unless I turn off PS for some time (assuming discharging caps) and then restarting. I find myself watching being mesmerized by your knowledge. Sure wish I never dropped out of EE classes 41 years ago.
I find electronics boring but what I do like is old technology. Watched one of Mr Carlson's videos and was impressed with his knowledge. So I watched another and another. Now I'm hooked. Nothing more satisfying then to watch someone who is extremely knowledgeable and good at what they do. His confidence that he'll fix whatever the problem is very impressive.
Hands down top 3 best SMPS educational video on RUclips.
4:55 "If it doesn`t operate, we will make it operate, not a big deal" :)
when I scrolled down and read your comment it was right when he said it.
And if we cant fix it, we'll just get a bigger hammer....lol
Hi Paul,
Thank you so much for sharing.
...I have to say, that I find, the videos you make are more than excellent. Your tutorials, presented with your obvious and observable depth of knowledge, and delivered in such a calm and measured manner, makes watching them highly educational and thoroughly enjoyable.
Thanks again.
Hey, glad you're enjoying David!
You have the coolest lab on RUclips as well as explanations.. thanks
I really enjoy the way you approach all of your repairs for us common folk not in" the know" can still grasp the fundamentals being applied in actual applications.
Thank you for spending what I'm sure is very valuable time to put this together.
Have you ever worked on high frequency Inverter GTAW (TIG) Welders? Would you ever be interested in showing how one is repaired if so.
well done and geared to someone like me with fair understanding needing refresher but have not toyed with some of this stuff in more than 15 years like they say """" if u don't use it u loose it """ am now at point in life i am hobbing in HHO GEN., power plant pulse and stabilizing power output from unstable supple v.. this gives me things 2 think on with other life experiences. ie: associate degree in computers & electronic, ham operator , service mechanic, hvacr tech, plumber , service tech n butcher in 3 packing houses, boiler tech . and "JACK OF ALL TRADES "BUT u no the rest. TY VERY GOOD
Awesome video. I like pausing when you show circuit diagrams and trying to figure out how it works, and then hearing your explanation afterwards.
I will be checking out your Patreon courses, cheers.
Glad you enjoyed!
A piece of Gem.
This is called the teaching madness.
No words, just request to keep up the great work 👍
Edit: jem to Gem
Another great video. The isolation transformer discussion was super enlightening. Recently I used an oscilloscope on a 1956 Admiral phono push pull amp that uses a power transformer. Figured I didn't need isolation. With the scope connection to the speaker (backwards) it created a hum. Even with the power switch off. I located a capacitor between the line and chassis ground caused it when the non polarized plug is inserted in reverse. Looks like isolation is good no matter what type of equipment is being tested. Thanks again.
Thanks Mr. Carlson for your gift of knowledge.
How can anybody give this gentleman a thumbs down. When I was young, I had to ride my bike for miles to the public library (L.A.,CA.) and take notes after doing an extensive search for the correct information so I could use it in my guitar amp designs. I know that sounds like a joke but I'm serious.
Learn what you can!!!
A very informative video sir. I am so glad that you stress the safety side of working on SMPSs and the use of isolation transformers. If you're lucky, the blue flash and the bang just gets your attention. If you're not lucky..........................
I often find it useful to just inject low voltage DC from a bench supply, instead of running full mains AC, while diagnosing a SMPS. That way you can safely check the switching and probe around as much as you like without having to be really careful.
That works ? Would have assumed that some sort of brownout protection would kick in !
That's what I'm trying to do,and as you said the brownout will kick in but you'll see some pulses before that, otherwise you can deactivated the protection since some ICs have a pin for that, or you can try injecting all the outputs not just the standby 5v.
Great tip - thanks!!
Outstanding example of a teaching video. Including the safety issues in a very direct way is particularly helpful. Thank you.
wow! Genius in electronics, genius presenter, genius teacher! keep it up!
My boss didn't like me to fix things like power supplies, "it's a waste of money". I did anyway, bought Solas for most new projects, never had to fix one, they are bricks. Excellent video, as usual. Kudos, and thank you.
excellent video. you are a real pro.
Happy to see that your number of Patreons is growing. You really deserve it!
Thanks Max!
I have watched quite a few of your videos and I have learned alot from them. Even watched some that are over my head and still have learned from them. Thanks. I will continue watching.
The ONLY caution I would add to your Video is to NOT handle a Power Supply without FIRST discharging the CAPACITORS . ALWAYS assume they are charged. That was what we learned in the Navy...
Just my $.02.
@MyName Here That's your asumption. If there is a couple of ampere through 24V it will kill you.
@MyName Here What about to main filter caps on the input? They can be charged up to like 350v.
he said a good practice... only if you get it positively...
Mr Paul just forgot to warn it. He is always warn it.
I learned that on my second TV repair.
I must have missed this one ,just watched it and what a brilliant explanation,im quite new at this and if you cant understand something you tend to put it to one side watching this has put my brain into 2nd gear, regards from across the pond 👍🇬🇧
just say brother, thank you for your kindness to share and teach us.Yesus love you
Your're Welcome!
Seriously, the first 5 seconds of the video i thought this guy is going to tell us how electronic troubleshooting in outer space is fixed. Very nice and informative video.
Just went by patreon, and started your talkthroughs series there. Awesome stuff, thanks for the content. :)
Hes very nice to listen to . Ive literally never said that before . i have a hard time focusing on people when they talk or explain things but man every word has my attention
I keep watching your videos. Now i could actually follow this video. From what i learned so far from you and what i knew, this video served another great lesson. I'm pretty glad I found you. Your a teacher I can follow and learn from. I will headed to Patreon and support you. Its only right. I gain so much from your videos.
Thanks Joe!
You are mostly the best teacher for electronics learning in youtube
Thanks Noel!
Good job ! I have a better understanding of a switching PS now. Thanks for the video.
Ten thumbs up! Excellent tutorial for working on 'hot chassis' circuits, which most modern consumer products are today. Floating grounds are the most commonly overlooked detail by techs today. (Afterall, who religiously uses, ever seen or even owns isolation transformers anymore? Those dissappeared with all the TV repair shops long ago)
If that power cord isn't a 3-prong or is missing the ground pin ... big red flag, it's probably a hot-chassis design that can kill whenever the cover(s) are removed. A quick check with a battery-powered meter for AC voltage between the wall plug ground and the stuff you're working, can make all the difference.
Looks like I have a lot to learn. Great video, I stayed with the video even though it was beyond my base knowledge.
Awesome job on the basics of switch mode power supply operation! Just now came across all of your videos and thanks for taking the time to make them. I've been doing electronics repair my whole life and still learn something new every day.
Thank you bro....thank you for teaching us....bless your heart.
This channel is one of the few remaining bastions of quality hardcore electronics content on youtube. Keep up the great work!
Thanks Alex...and it will remain that way :^)
I know so many have said it already but I have to say it again Thank you for all your fantastic informative videos .. Please keep em coming..
Once again, thank you Paul, for explaining electronics, in such an easy to understand way!
My pleasure!
Thank you, can you make a short video how to connect the oscilloscope, because in that video you just explained without showing how and thanks again
Yourself and Alan W2AEW have both missed your calling as teachers. You have a gift for relaying information in the right quantity and the right sequence. It makes watching the video actually fun while teaching very effectively..
Thanks Matthew!
What a fantastic explanation! Thanks a bunch!
Very cool explanation of switch mode power supplies. I have been studying NPN & PNP FET's over the past 2 days so perfect timing. You just gained a new subscriber.
Glad it was helpful!
As a basic power electronic repair engineer i realy like when i watch a professional electronic engineer!
big thumbs up mr Carlson
Hello Paul, thanks for you channel, it's very good.
About 50 years ago I built a 20W + 20W Mullard amplifier with a great deal of help. I Googled it the other day, it came up with 'National Valve Museum' - Gawd that made me feel old. EL34's Ah.
I won't go into details but I was lying underneath this beast when a wire dropped across my nose. It was 410V. I was holding the earthed chassis at the time. You are very wise to warn people. If I remember correctly I said "Golly Gosh", "Fancy That" and "**** the thing".
Even though most of your projects are well out of my comfort zone I do enjoy watching a craftsman. So many 'presenters' on You Tube are - let's just say 'overpowering' . Wide open spaces surrounded by teeth springs to mind. You are a pleasure to listen to.
I have taken up basic electronics as a hobby again. I'm in the throws of converting an old 120W Monacor line amp into a 40V - 6A power supply. It came from a pub, a pint of beer didn't do it any good. Most of the 'gubbins' are fine. I'm going to try the TIP35C's it has with an LM723 but I have 4 x 2N3055's on standby. I'm also fitting a 400W SMPS - variable A & V. I don't mind fan noise.
All I have is a Fluke, old but serviceable. Your video on SMPS and Linear power supplies was very interesting. I made a Joule thief and a radio ham friend went absolutely apoplectic. I told him I was going to make a 100W one with a long aerial but wasn't quite sure where to attach it. He thought I was serious - OOPS!
Thanks again for the videos they are very much appreciated.
Thanks for taking the time to write JP, those are some great stories... I Enjoyed! Glad to read your getting back into electronics again.
21:35 "And you might even destroy yourself" Classic. I have been earthed. Sent to ground. The final fuse has gone away, it gives and gives, we could go all day ;)
Mr. Carlson's Lab looks like he is the commander of his electronic space lab command center. His commands on the subject will make any problems be afraid to crop up and flee.
I would like to see from you one day teaching how to use an oscilloscope
I agree. I am especially interested, as a hobbyist with no formal training, on where you actually connect the probes when troubleshooting various components. Can you actually troubleshoot transistors with an oscilloscope? Where would you hook the probes?? Thanks
R Copo...... o-scopes are easy, its the spectrum /logic /network analyzers that’s tough, like looking at noise floors at -130db or beta gain of a transistor, when measuring the curve gets upsidown....yea buddy...and using the sig gens properly, its fun stuff....all good
++ for this request
W2AEW's "#232 More circuit fun transistor curve tracer using Stairstep generator circuit" is a really good video to help understand scopes.
@@W1RMD i think its little bit advanced. Btw, I liked that video too.
Hi Carlson, I simply love your videos. You explain all the relevant details in a clear and cogent manner, provide lots of practical tips and provide us the knowledge and confidence to attempt troubleshooting our devices that have stopped working.
I am an electronics hobbyist from Bangalore, India and I was thrilled when you said, "If it doesn't operate, we will make it operate, not a big deal". But when you supplied the power and the meter showed 24.01 V, I was disappointed. I expected the power supply to be in a non working condition and wanted you to diagnose the problem in your meticulous and systematic manner and do the needful to make it functional again. That way, there is a lot more scope for us to learn the art of troubleshooting.
Thanks for your wonderful videos and eagerly looking forward to more of them.
Thanks for your kind comment, and your input as well!
Will you believe I have never seen a switching power supply without a optic coupler in all my working years ? Even retired I'm still learning ! :)
THANK you for taking all that time to make this video. im the type that has to learn something every night before bed and im new to circuitry so this is amazing. keep up the great work
As soon as I opened this video, the Electronic Equipment all around the Teacher was almost reminiscent of the Flight Deck of a 747.
Really informed presenter here! Seems like a good opportunity to see if any true sign wave inverter explanation videos are posted to this channel..
The way I understand this circuit is that it's a pure square wave on the primary side out of the FET's. I'd love to see it taken one step further and understand how the bases are modulated in such a way to achieve "stepping" or better "true" sign waves. Thanks. And again, great video!
Deaf viewer here, would love to see subtitles to understand you better.
Thank You for your input Michael!
Great lesson with excellent explanations and use of test equipment to show what is going on in the power supply. Thank you for sharing!
good stuff thank you mr carlson
Brilliant explanation once again. I really struck gold when i dropped onto your channel. Thankyou
Really good like everytime thanks Paul /Paul from Germany :D
Thanks Paul!
Der Wissenskiosk by
fix cAr
fix car go to RUclips Craigslist
Best explanation for half bridge smps on youtube excelent work.And one thing to remind that you forgot to explain how te feedback works so it can stay regulated,but overall great work.
I'm heading to patreon
I have had a bad SMPS at home from a Wirecut EDM and had a vague notion that it was dangerous to test. Thank you so much. Now I know why.
Great video Paul, i like the inclusion of the oscilloscope. I recently got my first scope but not brave enough to use it fully yet, forgive the newbe question but could or should i use the scope on the same isolation transformer as the device under test? my area of concern is being tied to ground and frying something?
Noel Nestor - yea that is exactly what I was wondering. Would one require a second isolation transformer to float the scope? Although the scope manufacturers won't agree with that ...I would be grateful for advice on this as well. Love all the videos Paul.
Just for clarification i am using a rigol 1054z, so i think my options are using differential probes but thats expensive, using a maths function or running directly from a battery pack, i have tryed a 48v battery and it works but alot of hassle charging batteries
You isolate the circuit under test. Besides frying the scope you can fry yourself if you do not use an isolation transformer.
With an isolation transformer in place: if you accidentally contact the "hot" wire, you will pull it to ground. However, if you contact both the "hot" and "neutral" wires at the same time, you are setting up a short circuit.
-By putting your scope on the isolation transformer, with the circuit under test, you lose protection for the scope.- The ground on the scope will possibly be floating, unless you tie it to neutral. -- I was originally going to say the short-circuit risk described above is still present, but I don't think it is common to tie neutral directly to ground in equipment: that happens at the breaker panel. The scope may need proper grounding for safety reasons (to make sure stray voltages are not induced onto the chassis).
I suppose where I am getting stuck is by using an isolation transformer (as I do for the device under test), am I not just introducing a path to ground by probing with the ground clip? I'm learning at the minute and want to keep as safe environment as possible for me first of all and the scope also.
Noel Nestor
You are introducing a path to ground, but the isolation transformer isolates the circuit under test from it's normal ground.
That way, the rest of the circuit under test can "float" relative to ground. You still have to be careful due to the large voltages present.
I'm coming to your channel late, Mr. Carlson. I wish I had discovered you sooner. I have troubleshot a couple of SMPS's and got lucky. Most of the time, I toss them and order a new one. It is nice to see how to troubleshoot them. :) Thanks for posting. :)
Switch Mode Power Supplies, AKA Voltage to Smoke Converters.
I was avoiding fixing these things for a long time... for no real reason. Thanks for the excellent explanation!
You're Welcome!
only 2:43am, plenty of time for another video
Just very well done and absolutely great to have people share knowledge like this. There is life on the internet. Thank You, I am with joy going through your videos. Great job. / Patrik, Sweden
I think it might be fun to power and old tubed car radio with one of these. Paul I know you would be able to dial that in. ;)
Oh I'm sure...all over the band.
LOL!
Thanks for making this video Paul. While I have never used dual channels on a SMPS I now know the dangers of doing so.
You're welcome Steve!
amazing tutorial! please do a repair to a pc atx smps ! nobody has done that..
Will Do!
Yes please!
the repair would follow a similar line BUT a lot of failures in comp supplies are dud caps (bulging tops) main cause of failure followed by complete blowup of choppers (not worth fixing) but do check the caps also the same on mother broads. many thousands of machines scrapped because of a bunch of cheap caps dying.
Konstantinos Nano should make power supply with u mechanical motor running gears for diffrent voltages a pma generator with all the voltages at the right rpm but charged from solar or wind to capacitors runnning 3 phase permanet magnets simple to fix with hardly having to know so much.
Awesome video. Simple and going slowly through whole build. The only thing that I would change is that when you are measuring, the camera could stay on the circuit and the some smaller screen on the measuring equipment or vice versa. (I did not have chance to watch rest of your videos when maybe you applied it already but for this video this is what I would love to see). I was looking long for just this simple step by step description on how the PSU is working. Thank you very much! It is now much more enjoyable to learn this stuff.
18:54 Great advice on how NOT to hook-up your Scope's common lead to an isolated PSU circuit.
Thanks! This is the first time I actually understood SMPS.
Every time I open one of your videos I think I accidentally put on a live feed of the ISS
its so iconic. makes me happy
I spend every day repairing power supplies in high power professional audio equipment and whilst your video was informative it allows exposure to dangerous voltages. there's a much easier and safer way that doesn't want to kill you at the first slip.
you'll need a lab power supply and a few links.
Find out what your amps controller plus gate driver is then power up all the oscillator and drive circuits with the psu. a few bits of trickery are needed sometimes to convince the shut down pin to get the correct signals. simply put, the only time you need high voltages is to switch through the devices.
once all gate signals are happy and there is zero crossover then get a second pus and shove maybe 30v into the bridge rectifier and make sure the devices are switching current though the windings, and of course measure the output of the secondary rectifier voltage as a functional relationship to the incoming voltage.
no danger, simple and reliable
I need to get buttons made up that read "You're doing so at your own risk".
@UFOhunter: Not takes care of, but weeds out ;)
I call it a "Self Correcting Error". If "they" screw up with this i doubt they'll make that same error again. Hence, the error has been corrected.
A fuse "BLOWS". It doesn't "go away". Remember to speak in the language that makes sense to the masses.
Isolation transformer DEFINTELY is good advice! I was replacing components on an SMPS and completely forgot to turn it off. Kept thinking: "God, I swear I feel a little tingle every time the solder touches the board. Must be my imagination." No, it wasn't. Turned it over and the LED was lit indicating it was powered up the entire time. Surprisingly, it survived having random components taken in and out of the circuit. Thankfully, the isolation transformer did its job.
Couldn't they have simply driven the MOSFETs directly from the IC and saved some transistors and a transformer? The only catch is that they'd have to use 2 inverter gates (or even a 4N25 opto-isolator) at the IC outputs to provide a brief logic-high pulse to the gates, since the IC provides a brief logic-low.
No, there is about a 160 volt difference between the two gates. The transformer is required for that IC.
You can get different switch mode ICs that can directly drive the mosfets though.
Well, there's also the issue of primary-to-secondary isolation (ie. between the mains side and the low-voltage side). Yes, there are also PWM controllers that are intended for use on the primary side, but even those would need some sort of gate-driver ICs (if we're talking half-bridge designs).
I assumed this to be the case but I'm glad someone asked the question so that a knowledgeable person could provide the affirmation. Following along as a layman, I had the same question as Mr. Squires.
Rick Rose
Man you all must be electrical experts considering you are following all this completely
A great way to teach. Love your collection of vintage and leading edge equipment. You are a great Teacher Thanks much - RMc
If you are following along, yo are doing so at your own risk !
Just take care! :^)
Good job for making this video. There are few people videos about SMPS, and most of them they are not explaining so good.
Keep up the good work ! Thank you !
Ok I ordered an isolation transformer.
I know this is old but are you happy with the you manuf/model of isolation transformer? Did it require any additional internal bonding?
@@AN-kg4ei Quality import. So the transformer had the screws loose and one fell off. But easy fix. Works fine. Hard to mess up a switch, transformer, and outlet.
When I first opened up your vid I thought you were going to take us on a journey to the moon in Apollo ha. Seriously a brilliant explanation, I learned a lot if at least to leave well alone. The high voltage capacitors with charge left it them also pose a harmful risk of electrocution, perhaps worth a mention. A great lesson thank you.