Wow! What a smart and fast analysis of this SMPS with lots of explanations and analytical error analysis! You are a real genius! And of course i love your skills with the big soldering iron on tiny SMD components! 😉
My uncle (masters degree in EEE and CEng) used to work in a corporation where they made switching power supplies and they’d specialise in designing power supply boards that were extremely over engineered and expensive, with the objective of making sure it couldn’t be taken out and used by the consumer. There was one supply, 900 amps at 12 volts DC constant current, synchronous rectified. Thousands and thousands of components for active PFC, MOSFETs for both secondary and primary rectification among other things. The transformer had a primary on the board, but a gigantic ferrite core that extended vertically around 10CM before taking 90° bend like an L, before getting to the auxiliary, secondary and tertiary windings. They only sold two.
The main objective of a modern day engineer is to design a thing that will work the warranty period flawlessly and break down the day after - irrecoverably.
I love how far you dive into the functioning of the power supply. For me it was already junk. Even though I am an embedded hardware and software engineer
You are a real expert in power electronics, that was a real quick analysis and repair. I can't stand repairing anything that has a 'go bang in your face' potential. Having all the right tools really helps too, the thermal imaging camera is a real luxury. I guess the cat isn't interested in a ring tester, I mean, have you ever hear a cat frrrrt?
Nice approach to funnel down the components aided by thermal image, using the right tools save a lot of time. I just missed you taking a thermal image after the PSU was fixed just to compare the difference.
I've repaired a psu with similar topology, it was easy to follow along! Weird that those small signal transistors failed, I wonder what caused it. Maybe a high voltage spike, static electricity or something? Great repair in any case!
I love your soldering iron. I have such one as well, but using it only for heavy-duty stuff. I think you might be better off taking a screwdriver and a candle next time, that's more precise and viewers will love it 😄
Nice! 50 years ago upon passing the exam of my apprenticeship I was asked on how to trace a fault in a half dead SMPS. I said: Start in the middle with a scope. No thermal cameras then. Then divide the non working half int 2 again until you hit the faulty part. In your case of 3 faulty transistors out of 4 I would have replaced all 4 and then give the unit a soak test. Hope your cat agrees with me!
That is a recommended fault tracing procedure: Start in the middle and work towards the side not working. You can divide that side again if large. I look for faulty components first as he did as I am reluctant to work on powered circuits.
Power semiconductors are stupidly tough. As long as you don't cause power peaks large enough to blow them up, they can get hot enough to desolder themselves from the PCB and keep working until they fall off. That is over 235C board temperature with lead-free solder, 300+C junction temp.
@@DiodeGoneWild If the plastic/epoxy housing is 160C, the junction is likely over 200C. Also keep in mind when using a thermal camera that different surface materials and finishes have different thermal emissivity. Black pigment in the TO220 encapsulation has emissivity around 0.8 vs 0.4 for lead/tin and 0.25 for tarnished zinc. You need to calibrate your thermal camera for the type of material you are reading temperatures from. If your camera is set for the 0.8 curve and you are looking at a tarnished zinc-plated TO220 package's metal tab, that tab is much hotter than the thermal camera says it is.
The junction was close to 160C too, because with no heatsink, the junction to case thermal resistance is quite small relative to the case to ambient thermal resistance.
Wow...very impressive diagnosis and troubleshooting methods. I learn so much from you. Thank you so much for sharing. I am just curious though which charger did this come out from? Was it an ebike charger?
This is not complex. A real feat would be to design a resonant + sync-rectified PSU without the use of a proprietary IC - which I have done. Using the BC807/817 transistors to drive a GDT is a really questionable decision. They died because their max current is 0.5A, and the small SOT23 package can only dissipate so much heat… I tend to either use two pairs of SS8050/8550 in parallel or go with a larger package if space isn't a concern.
22:29 as l'm watching this video I have on my desk one of these, which just arrived and I've just opened the box 😅 I've seen it in one of your previous video so I ordered it. You already helped them sell one more 🤣
Using the BC807/817 to drive a GDT is a terrible idea. Yes, they’re rated up to 0.5A, but they are still small signal devices. The SS8050/8550 are much better suited for this purpose. But still, there’s only so much heat the small SOT23 can dissipate… Appreciate the old-school insta-heat soldering gun. Quite a neat SMD dismount tool!😂
Dear Sir, @17:37 the paper which has the schematic drawn on it is extended with a piece of scrap paper. What (type of) adhesive did you use? [Disclaimer]: I ask stupid questions.
Holy shit! That macro lens sure makes a difference for that thermal camera. I am dying to get me thermal camera but they are either complete garbage or way too expensive.
I think c945 transistor which one might be as alternative to one of smd faulty but i don't know second alternative could you tell me if I'm thinking right? Thanks
I cant ever trust whether or not im grounded touching fets like that anymore.. been bit one too many times.. itll always be my elbow touching metal on a desk or the chair.. ive also had a drop of sweat come off of my forehead and land right on the microcontroller pins and send a whole section of the board up in smoke..
А ещё на силовых транзисторах, надета ферритовая бусинка на затворе, хотя обычно, что бы снизить всплески включения и выключения, бусинки надевают на исток транзистора.
sometimes failures just dissapear and I hate it. last weekend I was struggling with an electronic transformer for halogen lights. It would not start up. I checked all solder joints and resolderd all of them and checked all the components. everything looked fine but it would not start up. so I replaced the DIAC and it started working. I measured the DIAC with the multimeter in diode mode and it showed open as expected. so I swapped it back in and the bloody thing still worked. very annoying
A diac shows as open circuit on a multimeter diode test. It needs about 30V to trigger. Diacs probably can suffer from an intermittent open circuit, just like diodes. The bond wire can be losing its contact with the silicon. The leads can get loose in the plastic package. Then it can start making contact again as you manipulate it or solder it. The intermittence can react to temperature changes.
@@DiodeGoneWild I also suspect some intermittence in the DIAC - I was just surprised b/c I have never seen one fail in this kind of application. Another suspect is the small capacitor in series with the DIAC that I had to bend to access the DIAC. the bending action may have fixed some intermittence in the capacitor. Or I have missed the solder joint despite being quite sure to have resoldered every darn spot.. I should have used an oscilloscope to verify but I don't have a way to isolate it.. oh well
Perfectly fine, as long as you’re not grounded and don’t touch BOTH of the exposed drains or anything else in the circuitry. If you do, you’d be in for a significant emotional event.🤯💀
I can still buy 300W Philips incandescent and halogen bulbs along with various brands of specialty/decorative bulbs at my local Home Depot. The big catch for general-purpose lighting is that LED bulbs are now 30-60% cheaper: for the price of two 60W incandescent bulbs, I can get a 6-pack of 60W-equivalent LEDs. Incandescent makes not sense unless you absolutely want/need them for reasons other than efficiently producing light. If I had to get a bulb as a ballast for electronics repairs, I'd get a T3 halogen shop lamp and use 100-500W bulbs in that. Spare bulbs in different wattages occupy far less space than high-wattage E26/27 base ones and installed bulbs are in ready-to-use rugged enclosures if I need lighting elsewhere.
But why in half bridge you say that its alright for one transistor to get hot? In my understanding both of them should be the same temperature. Oops I spoke too soon
Hi there! Can You make clips about electric motors as well once a while?! Just for a change!! you see people like me who are elctronic hobbyist looking for materials related to everyday life. Everybody loves savings right? why not going for a double win! at the same time learning about electronics and very likely to use it around my home to save a lot! would you please consider that? and similar subjects like that as well.could be an enjoyful change for yourself too. For instance talking about gas appliences and explaining how their electronic controls and boards operate or perhaps about trouble shooting!
Once I thought I'd found a big transformer, but it was actually an inductor with some kind of sense coil. The ratio in the thickness just wasn't right for a transformer.
I got the same leads as you, the thin pointy ones, they're nice compared to my fat ugly old ones that came with my Astro AI meter, but then i tested the resitance, thanks to my new tweezer meter (zoyi something or other) it has 10 miliohm resolution for resistance is the main reason i got it, much better then my multmeter. Turns out those nice looking probes are around 120 miliohms resistance, and my ugly old astro ai probes were only 50... Dont judge a book by its cover is the moral of this comment, please like and subsc... just kidding.
What is yours opinion about FNIRSI instruments and can U make a video about functions on osciloscopes and multimeters and what thermal camera u have? Thanks
Thou may not, apprentice. It’s top secret info, given only to those who have mastered the art of SMD soldering with an old ass insta-heat soldering gun.
As always, incredible application of an enormous soldering gun to replace minute SMD components
I aspire to be anywhere near as good doing similar! 😁
I think he is just flexing with his soldering skills .. a master of his craft can do the most amazing things with the crappiest tool 😆
Con quel saldatore riattacca le zampe alle zanzare
The worse the tools required, the better the craftsman.
Those big ones are not so hard. The small ones SUCK! especially leds
Wow! What a smart and fast analysis of this SMPS with lots of explanations and analytical error analysis! You are a real genius! And of course i love your skills with the big soldering iron on tiny SMD components! 😉
My uncle (masters degree in EEE and CEng) used to work in a corporation where they made switching power supplies and they’d specialise in designing power supply boards that were extremely over engineered and expensive, with the objective of making sure it couldn’t be taken out and used by the consumer. There was one supply, 900 amps at 12 volts DC constant current, synchronous rectified. Thousands and thousands of components for active PFC, MOSFETs for both secondary and primary rectification among other things. The transformer had a primary on the board, but a gigantic ferrite core that extended vertically around 10CM before taking 90° bend like an L, before getting to the auxiliary, secondary and tertiary windings. They only sold two.
😍
The main objective of a modern day engineer is to design a thing that will work the warranty period flawlessly and break down the day after - irrecoverably.
I love how far you dive into the functioning of the power supply. For me it was already junk. Even though I am an embedded hardware and software engineer
I actually like the longer videos.
Wow, your skills! Measuring components and knowing what they do is great, but knowing how to use a scope like that, is beyond me 😂 Respect!
You don't worry about how long the videos are, that's our job. Although I couldn't even imagine why anyone would, they can always skip ahead.
You are so good at troubleshooting. Explanations of steps are awesome as well. Thanks a lot.
10:26 you can't get more Central European than that shot outside
beautiful place :3
Thanks! Cat Treats & the dog if not vetoed by the cat. Excellent video.
Thank you very much for your support! Meow meow, woof woof :)
@@DiodeGoneWild😂🥰🐈🐕
Always a pleasure to see and listen about those things from You.
You are the master of SMPSs. 💪
Gratulujem k úspešnej oprave spínaného zdroja a ďakujem ti za toto pekné a poučné video.
Great, clear analysis. This is the real university of SMPS diagnostics.
You are a real expert in power electronics, that was a real quick analysis and repair. I can't stand repairing anything that has a 'go bang in your face' potential. Having all the right tools really helps too, the thermal imaging camera is a real luxury.
I guess the cat isn't interested in a ring tester, I mean, have you ever hear a cat frrrrt?
Nice approach to funnel down the components aided by thermal image, using the right tools save a lot of time. I just missed you taking a thermal image after the PSU was fixed just to compare the difference.
I've repaired a psu with similar topology, it was easy to follow along! Weird that those small signal transistors failed, I wonder what caused it. Maybe a high voltage spike, static electricity or something?
Great repair in any case!
Look at those big eyes!
Your cat must see perfect in what we call dark.
Super interesting repair, thanks for teaching me a bit about gate drive transformers + transistors in a bridge config!
10:21 😅😂😁👍🐈
U r the only channel i watch in 0.75x speed 😊👍 thx 4 ur videos
we miss these types of videos
Nice Polish alcohol!
It's cheaper ordered from Poland than it is here ;).
@@DiodeGoneWild What thermal camera is that at minute 13:00 ?
@@DiodeGoneWild Pozdrowienia z Polski!
I love your soldering iron. I have such one as well, but using it only for heavy-duty stuff. I think you might be better off taking a screwdriver and a candle next time, that's more precise and viewers will love it 😄
Nice! 50 years ago upon passing the exam of my apprenticeship I was asked on how to trace a fault in a half dead SMPS. I said: Start in the middle with a scope. No thermal cameras then. Then divide the non working half int 2 again until you hit the faulty part. In your case of 3 faulty transistors out of 4 I would have replaced all 4 and then give the unit a soak test. Hope your cat agrees with me!
That is a recommended fault tracing procedure: Start in the middle and work towards the side not working. You can divide that side again if large. I look for faulty components first as he did as I am reluctant to work on powered circuits.
Respect for the super hot transistor that stills good
Power semiconductors are stupidly tough. As long as you don't cause power peaks large enough to blow them up, they can get hot enough to desolder themselves from the PCB and keep working until they fall off. That is over 235C board temperature with lead-free solder, 300+C junction temp.
Only 10°C above the maximum rating doesn't destroy a semiconductor in a short run.
@@DiodeGoneWild If the plastic/epoxy housing is 160C, the junction is likely over 200C.
Also keep in mind when using a thermal camera that different surface materials and finishes have different thermal emissivity. Black pigment in the TO220 encapsulation has emissivity around 0.8 vs 0.4 for lead/tin and 0.25 for tarnished zinc. You need to calibrate your thermal camera for the type of material you are reading temperatures from. If your camera is set for the 0.8 curve and you are looking at a tarnished zinc-plated TO220 package's metal tab, that tab is much hotter than the thermal camera says it is.
@@teardowndan5364 That's why I use physical thermometers with a blob of thermal paste on the end.
The junction was close to 160C too, because with no heatsink, the junction to case thermal resistance is quite small relative to the case to ambient thermal resistance.
Excellent video. I love fix power supply Hugs from Brazil
I love this guy. Always great videos:)
Nice work.
Simple small problem hard to identify without Equipment .. but obviously not hard to repair with enough rosin XD
Thank you.
Thank you for your support ;) Now I can afford more rosin!
There’s never enough rosin!😂
Gostei muito do video e vejo os seus videos sempre que posso ...e belo felino....saudações desde Portugal
Wow...very impressive diagnosis and troubleshooting methods. I learn so much from you. Thank you so much for sharing. I am just curious though which charger did this come out from? Was it an ebike charger?
Love these mega complex power supplies. Wonder what engineers designed boards like this, entirely from scratch.
Pay attention to the end of video, when DGW discuss driving chip. But still great work of designer. Question is why those transistors died.
This is not complex. A real feat would be to design a resonant + sync-rectified PSU without the use of a proprietary IC - which I have done. Using the BC807/817 transistors to drive a GDT is a really questionable decision. They died because their max current is 0.5A, and the small SOT23 package can only dissipate so much heat… I tend to either use two pairs of SS8050/8550 in parallel or go with a larger package if space isn't a concern.
Wow, really usefull the way you detail everything. Keep it up !
❤ Goooooood and niiiiiiiice troubleshooting!
Nice repair!
16:55 The scene of Terminator being lowered into the molten steel adapted for germanium transistors
22:29 as l'm watching this video I have on my desk one of these, which just arrived and I've just opened the box 😅 I've seen it in one of your previous video so I ordered it. You already helped them sell one more 🤣
Using the BC807/817 to drive a GDT is a terrible idea. Yes, they’re rated up to 0.5A, but they are still small signal devices. The SS8050/8550 are much better suited for this purpose. But still, there’s only so much heat the small SOT23 can dissipate…
Appreciate the old-school insta-heat soldering gun. Quite a neat SMD dismount tool!😂
Another great video
Dear Sir,
@17:37 the paper which has the schematic drawn on it is extended with a piece of scrap paper. What (type of) adhesive did you use?
[Disclaimer]: I ask stupid questions.
Love from India ❤❤❤❤❤❤😊
superb video
Coffee for you; nice vid, thanks!
Thank you for your support ;)
Holy shit! That macro lens sure makes a difference for that thermal camera. I am dying to get me thermal camera but they are either complete garbage or way too expensive.
Please make a video on how you repaired the MESR-100, mine is acting weird too. Thanks
Great video
That was awesome!
👍👍 So nice!!
I think c945 transistor which one might be as alternative to one of smd faulty but i don't know second alternative could you tell me if I'm thinking right? Thanks
Sir, would you recommend a few sources to study more power electronics from?
“Power Supply Cookbook” by Marty Brown.
I think we need to get him a fancy JBC soldering station, but still this big soldering gun heats up in seconds so it isn't that bad
do you have a guide available for this kind of diagnosis?
I cant ever trust whether or not im grounded touching fets like that anymore.. been bit one too many times.. itll always be my elbow touching metal on a desk or the chair.. ive also had a drop of sweat come off of my forehead and land right on the microcontroller pins and send a whole section of the board up in smoke..
The control chip looks like some version of the NCV4390.
А ещё на силовых транзисторах, надета ферритовая бусинка на затворе, хотя обычно, что бы снизить всплески включения и выключения, бусинки надевают на исток транзистора.
Top video 👍🏻👍🏻👍🏻
Is it dangeroooos?
sometimes failures just dissapear and I hate it. last weekend I was struggling with an electronic transformer for halogen lights. It would not start up. I checked all solder joints and resolderd all of them and checked all the components. everything looked fine but it would not start up. so I replaced the DIAC and it started working. I measured the DIAC with the multimeter in diode mode and it showed open as expected. so I swapped it back in and the bloody thing still worked. very annoying
A diac shows as open circuit on a multimeter diode test. It needs about 30V to trigger. Diacs probably can suffer from an intermittent open circuit, just like diodes. The bond wire can be losing its contact with the silicon. The leads can get loose in the plastic package. Then it can start making contact again as you manipulate it or solder it. The intermittence can react to temperature changes.
@@DiodeGoneWild I also suspect some intermittence in the DIAC - I was just surprised b/c I have never seen one fail in this kind of application. Another suspect is the small capacitor in series with the DIAC that I had to bend to access the DIAC. the bending action may have fixed some intermittence in the capacitor. Or I have missed the solder joint despite being quite sure to have resoldered every darn spot.. I should have used an oscilloscope to verify but I don't have a way to isolate it.. oh well
touching a half bridge mosfets while it´s running is kinda wild 🤣🤣🙄
Perfectly fine, as long as you’re not grounded and don’t touch BOTH of the exposed drains or anything else in the circuitry. If you do, you’d be in for a significant emotional event.🤯💀
What incandescent bulb brand still exist in your country ?? GE, Osram, Sylvania, Philips ???
I can still buy 300W Philips incandescent and halogen bulbs along with various brands of specialty/decorative bulbs at my local Home Depot. The big catch for general-purpose lighting is that LED bulbs are now 30-60% cheaper: for the price of two 60W incandescent bulbs, I can get a 6-pack of 60W-equivalent LEDs. Incandescent makes not sense unless you absolutely want/need them for reasons other than efficiently producing light.
If I had to get a bulb as a ballast for electronics repairs, I'd get a T3 halogen shop lamp and use 100-500W bulbs in that. Spare bulbs in different wattages occupy far less space than high-wattage E26/27 base ones and installed bulbs are in ready-to-use rugged enclosures if I need lighting elsewhere.
👍
review new ikea charger please ;)
Maybe if there were several more stages of passive smoothing, it would still be in operation...
But why in half bridge you say that its alright for one transistor to get hot? In my understanding both of them should be the same temperature. Oops I spoke too soon
He said that's not ok
I never said it's ok
@@DiodeGoneWild Yes, you are right I misheard and spoke too soon sorry about that :)
Hi there! Can You make clips about electric motors as well once a while?! Just for a change!! you see people like me who are elctronic hobbyist looking for materials related to everyday life. Everybody loves savings right? why not going for a double win! at the same time learning about electronics and very likely to use it around my home to save a lot!
would you please consider that? and similar subjects like that as well.could be an enjoyful change for yourself too. For instance talking about gas appliences and explaining how their electronic controls and boards operate or perhaps about trouble shooting!
14:45 that left hand gets horribly close to the mains sochet xD
Once I thought I'd found a big transformer, but it was actually an inductor with some kind of sense coil. The ratio in the thickness just wasn't right for a transformer.
Niiiceeee......bloody hot..........
...i like your voice very much
Niiiiiiiice. ☺
I got the same leads as you, the thin pointy ones, they're nice compared to my fat ugly old ones that came with my Astro AI meter, but then i tested the resitance, thanks to my new tweezer meter (zoyi something or other) it has 10 miliohm resolution for resistance is the main reason i got it, much better then my multmeter. Turns out those nice looking probes are around 120 miliohms resistance, and my ugly old astro ai probes were only 50... Dont judge a book by its cover is the moral of this comment, please like and subsc... just kidding.
what do yo mean not grounded? are you floating?
Plastic floor on wooden boards, what's conducting the current here?
15v 300w would be nice for dead cars
14:57 and then he scoped all over the place
My internet speed is noob
Blooody hellllll. You’re a genius but you’re soldering skills need some serious help 😂😂😂
You try soldering with a shovel, then come back and report.
@ lmfao. Someone send him an iron.
I also solder with a soldering gun and have even built SMD stuff it works perfectly if you get used to it
This ancient soldering gun.....😨please buy something new it will make soldering much easier for you ☺☺
Please use a proper soldering iron 😮😮😮😮😮😮😮
Soldering guns are way better for this kinda stuff lmao
Excuse me, that is a proper soldering iron.
What is yours opinion about FNIRSI instruments and can U make a video about functions on osciloscopes and multimeters and what thermal camera u have? Thanks
may I know about the X and Y capacitor?
He's mentioned it a thousand times
Thou may not, apprentice. It’s top secret info, given only to those who have mastered the art of SMD soldering with an old ass insta-heat soldering gun.