Fixing a big Li-ion charger power supply

Repairing a 15V 300W switching power supply module from a battery charger. How to test a SMPS and its components, how to find the fault.

0:00 - Intro
0:25 - SMPS component description
2:29 - SMPS diagnostics without power
11:30 - SMPS diagnostics with power
16:52 - Replacing faulty components
18:49 - Post-repair verification

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[johnwelbourn]

As always, incredible application of an enormous soldering gun to replace minute SMD components

[Alchemetica]

Thanks! Cat Treats & the dog if not vetoed by the cat. Excellent video.

[rilosvideos]

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! 😉

[keithking]

Lord I miss watching this channel. Got to start "back-watching" videos I've missed over the last months I've been crazy busy (still crazy busy) .😊😊😊

[BritishEngineer]

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.

[menotyou]

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.

[keithking]

God haven't checked into this channel in good while now. Fixing E-scooters/bike's keeps me busy as hell.. I live in the centre of Ireland 🇮🇪 and the only place for people to get their scooters fixed is Dublin...!
And they charge 200 Euro for something id charge 50 Euro's for... They're so easy to fix and I always have a waiting list of minimum two weeks to a month when I take on more people needing help. Going to Dublin for hall sensor replacement costing €200 is out of most people's rage money wise. A set of new hall sensors can be anywhere from €7 to€10 online id charge €30 to €40 for that particular fix. Always a have a few brand new dashboards(the displays) 4 & 5 pin connectors. And some mother boards. If I it's to much work to to chase tracks and components to sort out the problem I just slap in one of boards that's needed that I'd have... "NEVER SHORT OF CASH NOW" and I learnt more about electronics from this channel than any other... So thank you Danny for your awesome information you give 👍🙏🇮🇪

[Georgy-]

Great, clear analysis. This is the real university of SMPS diagnostics.

[madsskov_dk]

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!

[d.k.]

Nice work.
Simple small problem hard to identify without Equipment .. but obviously not hard to repair with enough rosin XD
Thank you.

[threeMetreJim]

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?

[xkubasj]

Unbeatable expertise and deep knowledge. Respect, Danyk!

[tranxn]

You are so good at troubleshooting. Explanations of steps are awesome as well. Thanks a lot.

[tajtrlik]

Gratulujem k úspešnej oprave spínaného zdroja a ďakujem ti za toto pekné a poučné video.

[Robbedoes]

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

[LawpickingLocksmith]

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!

[davidhollfelder]

Bloody Hell .. shorted ..
Excellent skill and narrative for this repair .. nice …

[WagTsX]

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.

[LMB]

10:26 you can't get more Central European than that shot outside

[meowme]

10:21 😅😂😁👍🐈
U r the only channel i watch in 0.75x speed 😊👍 thx 4 ur videos