850W computer power supply - how does it work (with schematics)

Today I tried to repair a big 850W ATX computer power supply. It had quite a lot of faulty components, so instead of fixing it, I decided to reverse engineer some schematics, explain how does it work and do some experiments on it. It didn't go horribly wrong, just horribly long :).
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[@lakiza55]

Bloody hell is all i can say about this one. Studiying EE for 4 years now, took a break to watch a new video from my favorite YT channel. This is some next level engineering space magic, gave me a headache halfway through. Can't even imagine the amount of work and effort you put into this video, and i'm actutally glad you decided it's not worth repairing/not repairing it just for the sake of the video. It's appreciated, no doubt about it. My mind is simply blown by how far you went in on this one, and the fact that you're sharing all this knowledge for free. But you still owe me a fire extingusher for the headache ;)

[@bashaaksema94]

Haha nice

[@bashaaksema94]

EE here too xd

[@MassimoTava]

I can only imagine myself replacing all the damaged components only to turn it on to see all of them burn up again.

[@lakiza55]

@@MassimoTava lol, exactly. Recently had a cheap TPA3116 class d audio board fail on me, the chip went short-circut. Took the chip off, measured the resistance between VCC and GND and it was a ok. Soldered a new chip in and it instantly failed short-circuit when i powered it up. Obviously, something else was causing it to pop. So yeah, you can basically replace every single damaged component on the board, but you can only pray that it will work if you don't know what actually caused it to fail in the first place.

[@Conservator.]

Lazar Šaronjić A neat trick to prevent blowing up a (half) repaired amp, is to limit the amperage. You need bench power supply for that or use one of those cheap programmable voltage regulators. Search RD on AliExpress.

[@nosafetyswitch9378]

PRE-LIKING cause a teardown of an 850W PSU from diodegonewild IS going to be WILD!!!!!!!!!

[@bashaaksema94]

Yes!

[@MassimoTava]

It’s going to get quite a bit of attention from the gaming community. So a mix bag of very smart people, kids and trolls. Grab the popcorn.

[@previousslayer]

@@MassimoTava you mean "BREAKING NEWS ENERMAX IS NOW OFFICIALLY TIER 5 FIRE HAZARD ROFLMAO"? certainly happened before

[@juanmartinvk]

I pre-liked because of the cat

[@BillAnt]

Hope DiodeGoneWild didn't get electrocuted since he hasn't out out any videos in a couple of weeks... hoping for the best. ;)

[@accordionrepairman9572]

Watched and studied it all. Repairing a new never used new Apevia Signature ATX-SN1050W 1050W 80 PLUS Bronze Power Supply I bought for $10 on Ebay ...not working. I traced from 110VAC input to the outputs. Single cap for the +180vdc after the input bridge, unlike most with dual caps but that was the only power reading I was getting. Nothing was turning on. All the semicons tested good. So figured I need to find where the +5 vdc was being supplied from first ...the small transformer and associated ic next to 2 opto couplers. All looked and tested good and found the +5 vdc from that circuit. So i traced the +5 vdc from there and found a mini crack in the +5 vdc very thin 1mm trace on the edge of the circuit board at one of the 4 mounting corner posts. Apparently the box had been dropped with enough force to move the pcb enough to crack the trace. Solder bridged it ...success. Your info helped me track it down. Thanks

[@kendoty2463]

Weird it didn't break the board. . .

[@aivansama6265]

You can hear the excitement on his voice when the PSU starts to smell :D

[@humblehostile7946]

When

[@ayzues9525]

@@humblehostile7946 2:59

[@ahmedkotb3912]

I work in a company where we design these power supplies with even higher power ratings. I am currently working on a 3kW AC-DC power supply. I really appreciate your knowledge and the ease with which you handle these things. I am new in this industry and I struggle to understand the supply if I don't have a schematic and PCB layout with me. So I am curious to know if you actually draw the schematics from your own analysis? If that's the case then you are a super hero :D Plus, your cat makes the videos even more enjoyable!

[@AS-ug2vq]

First of all, take high definition photographs. Now zoom in and draw the circuit using layers in Photoshop. Proceed from there.

[@omniyambot9876]

why are you guys underrated

[@TROLOLz0r]

"This is dodgy, lets plug it in" This is why i love you . Stay safe though!

[@joshuavaz1008]

Super Dodgy

[@KrotowX]

In general same what ElectroBOOM did 8 years ago :)

[@CoolKoon]

@@KrotowX Not quite. This stuff really CAN kill unqualified wannabe repairmen.

[@sincerelyyours7538]

I have a similar 750W P/S needing repair so I was looking forward to a full repair of the one in the video, but I understand the reasons for not doing so. Sometimes the damage is so great as to render any repair effort too costly in time and materials, especially when inexpensive replacements are so readily available. However, I do appreciate the detailed walk-through, and the experiments with the working sub-sections were very enlightening as well. Love the accent, BTW, it forces me to listen more intently and I therefore learn more.

[@stewartcaldwell5299]

I'd love the case, just empty. Then I could put my puny PSU in it, and impress people.

[@octavmandru9219]

You are the king of the SMPS

[@randydicotti3975]

Sir, you and your sense of humor make learning electronics a whole new adventure. I must donate !!!

[@bencemarta5222]

I've been looking fore something understandable about ATX power supplies since I'm into electronics. And finally after years I found it :D Huge thanks!

[@martinda7446]

That was so funny...The cat....the primary paw, then the censored tail end....Very, very funny.

[@YoDay]

"do not open cover" So we can't open it ... . . . . . Just joking !!

[@rachael1090]

That oscilloscope is from the USSR. Man that thing is cool. I like Soviet era electronics and mechanicals.

[@senorcapitandiogenes2068]

"I can smell something beeehrning"

[@Poliacido]

LMAO

[@ix.cryo1]

@@Poliacido 😂

[@saarike]

Really great information about pfc atx-power supplies. Thanks it was nice to watch and learn something.

[@plamenpetkov6958]

And on Russian scope!!!

[@saarike]

@@plamenpetkov6958 Yes :)

[@rodrigoacosta9708]

The amount of knowledge and detail of your explanations are simple incredible, keep such a great work!! Hope one day I become at least a 50% as good as you are with electronics!!

[@odczynnik]

I have the same Makita:-) one go the best small battery driller and very strong:-) working fine over 8 years, and I'm using it almost everyday! Grate video like always, thumbs up 👍

[@tekvax01]

WOW! A very clear and concise explanation of a very complex switch mode power supply! Excellent job sir! You really know your stuff!

[@Den_Electro]

friend, please look at my diagram kzbin.info/www/bejne/qZOaXpp4pr19qs0

[@AlexanderBukh]

My trusty Cougar CMX 800W went south recently, with a loud bang, during an attempt of powering up a PC after a couple of weeks of standby. I am watching this with a tear in my eye. But it has served me for some 6 years. I will attempt an investigation after setting up a bench.

[@Phil8sheo]

Caps exploding most likely. Good luck.

[@superdau]

A bang when switching on (at the switch, not from standby) is quite often the inrush NTC. I had those explode quite violently a few times. You will know when you have pieces coming out of the PSU when opening it and a place with two component legs sticking out of the board ;) .

[@AlexanderBukh]

@@superdau i am sure it was not an inrush issue, i merely pressed power on button on the front panel of a pc. As i said, psu was in standby for weeks. Other tech in the same room unaffected.

[@uncontrollabledogs3791]

Wow! Watched the whole thing. You've got it down my friend. Wish i had your EE skills. Super informative vid. Keep posting.

[@IkmalRusli]

He is doing it right when he said "Do not remove this cover I'm just joooking"

[@daviousmaximus6446]

Talk about going beyond the call of duty. I learned so much from this one video it's amazing. Thanks so much. PS. I love your accent, it makes me smile.

[@abeditani8293]

Thanks . It help me alot to knows the way of complexity powersupply how it work . This things take alot of time to know . Thanks

[@boydmcree9085]

thank you for such a detailed description and explanation of the working, I want to build a similar supply for solar power panel in series with the power correction for open cicurt voltage.

[@rogeronslow1498]

The dc-dc converter is the LLC topology. It's a variable frequency fully resonant design operating above resonance. It has lossless switching on turn on and turn off edges so is quite efficient. Power output is controlled by increasing or decreasing the frequency. Power output increases as the frequency is lowered and approaches resonance, but must never reach resonance or lossless switching will be lost. The topology has pro's and con's but does result in quite a high power density supply. The dynamic range of the LLC topology has a limited dynamic range and is best run from a pre-regulated PFC stage. This topology is often used in 48v telecom PSU's for efficiency reasons. They are more complex to design than PWM converters and I always relied on computer modeling and simulation. Also, they are unbelievably quiet from an EMI perspective due to the soft switching.

[@felipebarreto10]

*FULL BRIDGE RECTIFIER IS NOT A PUNY SINGLE DIODE!*

[@stewartcaldwell5299]

Uh oh. Now the full bridge rectifier jokes again !

[@rpbajb]

DGW is so knowledgeable, he must have a doctorate in electrical engineering.

[@vaclavtrpisovsky]

He 'only' studied economics, but his knowledge comes from 23+ years of experience.

[@AndrewGillard]

It's possible to teach yourself so much through sheer passion and interest in a subject that a university course won't really teach you very much, in which case, why waste several years of your life (and vast sums of money, if you live in a country that doesn't believe in investing in its own future...) to learn basically nothing? Unless you need the piece of paper in order to get potential employers to even consider your CV/résumé, anyway 🙄 (But thankfully a growing number of companies are accepting that people without a degree can be just as qualified - if not more so - than people without one. Experience is worth ten times as much as a degree for a lot of subjects!)

[@stm3252]

The best EE channel on youtube hands down!

[@sujoybha]

Just FYI, the resonant half-bridge is used to reduce (eliminate) the switching losses of the mosfets. Thanks for the amazing videos and keep safe. Seeing you test 360V dc so casually raised my heartbeat.

[@Den_Electro]

friend, please look at my diagram kzbin.info/www/bejne/qZOaXpp4pr19qs0

[@tw11tube]

It is quite likely that the 1N5406 diode in the aPFC circuit is not just used on the initial charge of the output caps, but also in standby mode. It's state of the art since years to bypass the active PFC in standby to reduce standby power. PFC is required in the European Union for loads of 75W or more, so there is no need for the "overcomplicated control circuit" (quoting DiodeGoneWild) to run in standby.

[@tw11tube]

Got to the thirty minute mark: You already observed that the PFC is indeed off in standby. Also you provide the same explanation. Seems like I might indeed be right on that. :)

[@graxav]

Just exploded my PSupp fuse entirely - this vid is pure gold and the cat - that's a proper dude who makes space for his furball!

[@AvixkThePig]

I loooove your battery backup idea. I may expand on that and make a... safe... version

[@MoonDoes]

Thanks for being meticulous in your videos.

[@LunarHermit]

Very interesting learning about how these things work! Also answered why some newer PSUs have significantly different sound characteristics at low loads.

[@Den_Electro]

friend, please look at my diagram kzbin.info/www/bejne/qZOaXpp4pr19qs0

[@JesusIsLordofMybeing]

Awesome explanation my friend!! You sure know these confusing supplies very well. Love your humor on the subject as well. Thank you!!

[@Dusankk]

I like that Soviet made oscilloscope that you are using - Sdelano v SSSR. You are doing wonders here with electronics bro, keep up the good work !

[@algator55]

GoneWild I heard on eev blog some Shiite talk that you weren't as advanced and electronics as they were but I disagree, I watched both your videos for years and your videos are more knowledgeable and advanced than eevblogs 👍

[@binarybox.binarybox]

Another very entertaining and educational video...thank you.

[@Miata822]

Best video so far, I really enjoyed this detailed deep dive into the function of power supply components.

[@Den_Electro]

friend, please look at my diagram kzbin.info/www/bejne/qZOaXpp4pr19qs0

[@ElectroXa]

you got a nice project box with a fan 👍 I love switching power supplies, there is a lot of useful components to reuse ( if not blown 😂😂) big blue thumb 👍👍

[@robson6285]

Absolutely usefull to watch this video. There was a lot to learn about things totally new to me, especially in this detail. Exactly the usefull details, very clever and good to understand drawed and explained. Indeed, this was very worth watching with full concentration. Glad i did, and some of the most interesting bits i had to watch a second and sometimes a third time to get it really, to learn it usefull.. Oh I simply love this channel. His real usefull knowledge this clever diode teaches here, and even for free!?

[@raminrazmjo8478]

Thank you so much man. You are the best electronic enginier that i know. I impatiently waiting for your next videos

[@mostafarahmanian1276]

its some university courses in action !!! EXCELLENT!!!!!

[@cindydurrwachter8453]

Fantastic I am getting ready to work on about eight or nine modules that are very similar and design. This is and will help me quite a bit so far I do not see any burnt components but they are blowing the input fuses. I am hoping that whatever is happening is the same part on all They are using the automatic PFC which your video taught me what that is I could not figure out what the hell that stuff was. It is probably using DC to DC conversion like your supply also.

[@Bodragon]

(4:20) - Plural of *_"ATX"_* is *_"ATXs"_* One *_"ATX"_* Two *_"ATXs"_* (not _*"ATX's"*_) > I love your your channel. Keep up the *_great_* work. I especially like the Jacobs Ladder arcing type stuff that you do with old MOTs (not MOT's, haha!). I know many of your fans will be annoyed, even angry with me for pointing this out. All I can say in my defence, is that if *_I_* were in *_your_* shoes, that is, presenting KZbin videos in a second or third language; certainly *_not_* my mother tongue, I would be grateful for any helpful language/grammar advice. I think I know you well enough to assume that you will not take offence at this comment. Unfortunately, I do not think the same can be said for your legion of loyal and devoted fans. So, to *_those_* people, I apologise and leave a couple of words of wisdom for them to dwell upon: *_Grow up !_* >

[@dirface]

You could use some writing advice yourself.

[@Bodragon]

@@dirface How so ? Please enlighten me. >

[@coloradowilderness3139]

Learning Electronics 20 years. But DiodeGoneWild far exceed me . Need to change all BSC EEE books. Thanks

[@kampkrieger]

suuuuch an amazing video. You are a genius! Some people dont understand those thing. Others do but have no clue explaining it, because everything is so easy to them. you on the other hand besides beeing fun to watch because of you accent.. no i mean because of the things you have and use and do, are explaining it just step by step

[@supul32]

This is exceptionally well explained. Thank you very much!

[@mikeflosse4538]

What an enormous video!!! You made my day. Thank you so much for your big lesson

[@chrismr3972]

Regulation will be achieved using the PFC voltage, rather than some complicated frequency change altering tuning. The turns ratio of the main transformer and the input voltage are all that's required for regulation when the output has synchronous rectification (MOSFETs used in secondary instead of diodes). The two 100nF 800v caps are there to make sure that any DC imbalance in the drive doesn't end up prematurely saturating the transformer. (Imbalance being one drive MOSFET being on slightly longer than the other, which is almost impossible to prevent).

[@dktr2]

The cat knows it all, but it doesn't give a shit.

[@Kaxlon]

At 15:15 you can see a spark jumping to his pointing tool. =)

[@samslog]

Good that you did not try to repair a cascading failure like that. This video is great because every sub-topology is broken down on each sheet of paper and is research topic in itself. Eg: at @26/ mins the diode transistor pair is worth further research and a great one for including in power supply designs.

[@johnconrad5487]

This is an LLC topology. it has a VCO to regulate the output voltage

[@johncourt9580]

A great explanation of a complex circuit

[@haczyk84]

Properly exploded :) good video, I never had resonant regulator on my bench, learned something new, thanks!

[@vonnkimuelcortez208]

Sir thank you for this GEM! You made me wanna check out may broken 650w PSU thank you!

[@DanieleVetrucci]

Very good job and the CCCP oscilloscope and the old calculator are very fashinating

[@minkorrh]

That's a very cool little PSU test board you put together!

[@clfung2008]

A very good explanation ! Thanks for sharing !

[@halfbeardsilvertongue5129]

I liked it and saved it for later, but I'm obviously not well versed enough to follow it very well. So many people seem to follow it perfectly is what tells me I'm still lacking in my understanding of how to troubleshoot things like this. (sigh) I will keep trying though. Keep up the apparent good work, sir.

[@Shadow_of_STLKR]

21:55 xD Censored

[@markiangooley]

Oscilloscop is my guess at what the Cyrillic letters are. Wow, it’s an oscilloscope!

[@bluerizlagirl]

The letters are actually: O s (ts) i l l o s k o p.

[@enigmaticmf]

Dave would love the name of that relay: "Goodsky". :D

[@ovalwingnut]

Dang it. I had it all figured out until your cat mooned us... 🤗 P.S. Best APFC explanation bar none! And I got to get one of those rotatee switches. Very COoL. Thank You 💜

[@hakimyusuf5370]

I like how you explain dan draw it 😊

[@nickpelov]

Thanks! I didn't know how PFC works in these power supplies.

[@edinfific2576]

You have a ridiculous accent, but your knowledge and understanding makes up for it. I would rather listen to a good explanation with a bad accent, instead of no explanation with some crappy "music" blasting over the video. Great work, much appreciated. Best wishes from Bosnia!

[@kaletsugas]

I've watched from another atx power supply teardown that the relay in the pfc section near the ntc is for soft start.

[@kermets]

I was thinking from the length of the video and hoping you could not help yourself and have a go fixing it..... But know the time spent would not be worth it....thanks so much

[@jd4434]

Love your way of explaining 😂

[@misium]

Excellent walk-through.

[@1pcfred]

Nice Japanese Nippon Chemicon capacitors.

[@andiyladdie3188]

Very nice explained! It seems like a lot of hard work was put in designing that PSU, not a cheap one that's for sure. I think the culprit may be a tiny little spider or bug that came in contact with the pins of the gate control transformer. Good Job!

[@stewartcaldwell5299]

If so, he won't do that again !!

[@KaisUK]

This video is really welly done, I still wont be able to fix my PSU though as I need troubleshooting steps to go through. Do you have a video on that when you have +5VSB but nothing else works?

[@kacpreusz9911]

My phone is shutting down randomly specially when i carry it around in my pocket, it gets very hot (the motherboard gets hot when i use it the battery temperature is normal) and the battery holds the charge comparably to the... Blacharka (i don't know how to say that in English) in an Lada Samara. Can the overheating and shutting down be caused by the battery?

[@kacpreusz9911]

@Против Глобал I tried to factory reset it and it's the same. I read on a forum that this is caused by the battery craping out.

[@kacpreusz9911]

No the battery is just as good as Lada Samara. I had one it broke every 10km the battery is just cold

[@kacpreusz9911]

It isn't that hard. I just need to remove the back glass panel using some heat and prying then unplug the battery and remove it also using some heat to make the adheasive soft and easier to remove

[@abhijitborah]

Wonderful tester, you got there.

[@cariculum]

I have an ATX power supply with an unknown IC UTC 7608D. Have you ever came across this?

[@michaelturner4457]

So it must have made quite a loud bang when it went. I've had PC power supplies go bang before.

[@alanclarion6765]

This man has the finest accent on planet earth.

[@nguy80303]

Very nice. I feel you are getting too close to dangerous voltages. Hope you stay very safe

[@toweleeielite]

so whats the most likely faulty component when a PSU randomly turns off? and i dont think its heat related.........

[@KSCPMark6742]

jeez, poking around in the psu with first a scissor, then a screwdriver, then a metal probe... Extremely informative nonetheless

[@geoepi321975]

Hi sir diode, can you bridge 12 v and 3.3 together to boost the voltage up ?

[@kwazar6725]

Nice. Surprised on resonance controller. Not common olde garden smps. Cool.

[@ElektrikDunyam]

Thank you...

[@HDXFH]

Nicely built psu

[@scutoff]

Мой английский не очень хорош, но я все понимаю. Классные видео, давай еще!

[@nsns1996]

Well explained, thank you

[@publicmail2]

I drive my wife nuts when I keep saying HEEEEEEEERRRRE!

[@KasparOnTube]

next time try CAPACIIITOOOOOR :D

[@joeexabyte4431]

32:36 can you make a video of how exactly the circuit works with two mosfet and one inductor? how does the voltage drop occur? what is the role of the inductor? does the voltage drop only work when a load is connected behind the inductor? Why do you have dc and not ac, so no diode after the inductor? how is the inductor calculated? laptops use the same switching in the power supplies, but can't find anything about the circuit, i don't know if this circuit has a special name?

[@ivanpesl1287]

Excellent video. Particular query, Where can I get the diagram for ATX 850W POWER SUPPLY ULTRA X4? YOUR COMMENT, HOW YOUR VIDEO WILL BE OF GREAT HELP. Thank you.

[@rahmanocawni5618]

Hi friend. How do you know the circuit exploded referencies

[@totalchips6547]

Bloody hell, you forgot this time your fire extinguisher!!!.

[@MuhammadSalman-be1qz]

My Corsair AX1200 sometimes works for 10 minutes, sometimes half an hour or more and then the computer shuts down. Then it doesn't turn on at all for hours. After a few hours it start working again. What could be the problem

[@ariewijaya1679]

why in resonant psu the pwm chip located in the secondary not in primary like 85+ psu?

[@SagePatrynXX]

Brother has that brand although his is a 1000 watt one. never a problem, usually a good brand

[@SagePatrynXX]

btw love your hack. I just know sometimes the single wire hack to trick it to turn on although the one wire hack is intended for more permanent power

[@Bob3519]

Wow! Another great video. Thank you.

[@FastLikePuma]

I wish I had your tester!!

[@bukucsjozsef9630]

1:07 active Power Fan Control - in terms of older AT power supply. Personally not think in the past to the PFC transform a Power Factor control.

[@zeusjuri4694]

Nebo je to výsada výhradně svářeček?