I was immediately bothered with seeing something conductive right across the isolation… seems like an accident just begging to happen. The labeling on the outside is a definite red flag. Rather scary device.
I was going to ask about that. Is it not a bad design to allow anything conductive to bridge the isolation? Even the heatsink. Pressure to design a small PSU whilst also cheaping out on the components. If the PSU were more efficient it wouldn't have needed such a large heatsink in the first place.
@@felixokeefe if you were designing a PSU for best reliability, on the basis that it is going to be in a sealed plastic enclosure, you would have lots of sheet metal inside to efficiently spread the heat over as much of the box's surface as possible and to therefore minimise the existence of hot spots. Keep the components uniformly cool, have them last longer. So there is some merit to what was done here - it just wasn't done right. And the small blob of white goo connecting the metal to the plastic case is a bad joke - shows that they hadn't thought it through or didn't have proper communication between the designers and the manufacturers, or the manufacturers just didn't understand or care how to do it right.
@@Rich-on6fe you make some good points. I've seen similar style PSUs where the heatsinks have been wrapped in Kapton tape. Presumably to protect against this type of failure mode.
Poor design. They took the trouble isolating the high & low sides of the PS on the PCB (including notching under the optoisolator), but then bridged the isolation gap with the heat sink.
Doesn't look like a genuine Surface AC adaptor though. Just a shitty 'chinesium' copy with a LOT of cost cutting and shortcuts compared to the original ones. Its way larger than the original ones too, MS make some fantastic PSUs including in their consoles, this ain't one of them.
Probably another revision. Just look at how the other corner is cut diagonally, which might have been better for the faulty corner rather than the one with the USB port (which isn't even in the cut off part).
My “cheap replacement power supply” story: I was working with an audio testing company and we spent hours trying to figure out where a certain noise spike was coming from in our device. A lot of audio and cellular test equipment was in use, and all of it was controlled by a laptop computer. Out of frustration, I unplugged the laptop power supply and when we reran the test the noise spike was gone. The power supply turned out to be a cheap aftermarket one. We tossed it in the trash and got a genuine one from another computer and had no more troubles.
@@silverdragonslair They srls need to change CE to somethink outher like European Certificate of Conformity (ECC in short). Because be real here China do this special and for most of consumers it's hard to spot a difrence. And as you see even genuine europen parts and certyficates print this wrong...
It can have been a simple error in producing and lacking of QC. For example there is a cutout on the plate that makes little sense right now but if you turn the plate around, there is some distance between high and low voltage parts. So, maybe someone was just putting the plates in the cutter the wrong way round and cut of on the other side, having no knowledge of where it was going to be used. Then placed on the boards in the cases and shipped without further good checks. Of course works when it works untill boom. By the way, Clive, was the heatsink not soldered well on the board so it could move, only fixed with the screw on the transistor-package?
@@elvinhaak That heatsink covers all the components so if any checks were made on the board they would have to be done before the heatsink was attached, there was nothing holding it apart from the transistor either and it also looks like the plate was cut wrong, it appears they were hoping the heat transfer paste would be enough to hold the plate in place by sticking it to the plastic case and prevent it moving around too much ! There are many issues that should be picked up by quality control but they don't care about quality, they only care about sales.
As a designer involved in designing equipment to meet the requirements of the International Standards marked on the case, it is totally obvious that even if the power supply met those requirements when it was submitted for testing, it certainly doesn't in its current form. Whether or not that is the case, and I doubt that it was ever submitted for testing, it means that ALL the Approval Markings are either invalid or fake or both. The issue of rampant deception, safety issues and poor quality control is not just overly common in Chinese Products, it's typical. Just less so in products supplied with "Branded Products". CAVEAT EMPTOR!
You mean that there's a chance that even a reputable brand that outsources manufacturing of a product to a Chinese OEM may actually be getting a fire hazard that doesn't follow all regulations?
In Germany they did some mass testing of DC adaptors, quite a lot were completely unable to meet the power requirements marked on the case. Probably over 80%. So it's wise to buy something like 2.5A if you need 1A.
@@a4andrei The difference is a big brand will carry out testing prior to inclusion of the unit in their product. Load testing, vibration testing, temperature chamber testing.
@@chinchan9 I think the issue is that even if they submit a compliant design for testing/certification, they then progressively change it to save cost, without ever resubmitting it for testing and certification. Unless you have your own eyes on the ground at all times (like large companies like Apple, HP, etc. do), Chinese companies will take liberties to reduce cost, hoping their client won’t notice. When the client does notice, they’ll undo the last change, but they’ll continue trying new changes. (There’s a great book on this, “Poorly Made in China” that I recommend.) For sure, there are Chinese companies (like Foxconn and Quanta) whose business model is based on _reliably_ high-quality, to-spec contract manufacturing. But it seems they’re the exception, not the rule.
@@Em.P14 that's what makes big Clive's videos so good to me. He's not being all crazy to try to capture our attention, he's simply incredibly interesting on his own and just let's us tag along.
"Vibration during transit" is also my guess. That toroid was not secured. I've repaired many Anton Bauer chargers for pro camcorders which had an identical choke. Luckily, when it broke off it didn't short anything- it just stopped working. A little solder and a lot of hot melt glue fixed them.
@@tookitogo - difficult with existing products, but with that type of inductor, I prefer a nylon cable tie holding it to the board via holes purposely made in the board.
Yet another hard learned lesson on not to use cheap clone power supplies with expensive equipment. There is a reason why the genuine replacement power supply costs more.
The reason genuine psu's cost more is greed. As this shows just a single component placement was the issue so there are plenty of cheap psu you can buy that are great.
@@jasonwilliam2125 agreed, just get a electrical engineering degree already. I always open cheap PSU's and Chinese electronics to add insulation/upgrade wires and prevent problems. I have an 800W PSU i bought for $23CAD including shipping thats been working great for over 2 years now.
@@Mister_Brown I ever wondered if they were! But I absolutely hate the original ones, they're terribly unreliable, 80% of those I have in my company stopped working and I'm not sure it was the DC cable
@@fabiosemino2214 I've had numerous Surfaces and none of their adapters have failed. I still use an original i5 Surface Pro from 9 or 10 years ago and it flies along with windows 11 (modified to not require the TMP of course). The worst I've seen brought into my repair shop for fixing are users treating stuff badly and the cable being kinked and frayed to the point of internal shorting. Pretty much and device marketed for its portability is going to see some really bad user habits with the cables.
As a "retired" EE, I am reminded of the trinity of production. Cheap, fast, good... pick two. This device was obviously had a rushed design to sell at a low price. Like most cheap Chinese crap.
We had the exact same problem (with much less injurious outcome as we had e fuses) at my former workplace. The "fix", which was more of a workaround was to put heatshrink around the whole inductor, which worked of course. A virgin board was fine, but stick it in a container and ship it half way around the earth, yeah, that inductor moved. Bit crap really.
They did a good job isolating low voltage from mains, then completely violated it with the heat sink/shield. Just simply dropping the PSU might have made the inductor touch heatsink.
Grounding that heatsink was the BIG design fault. Also another thing I notice is there is no MOV or spark gaps in there to deal with any sort of mains spikes. It could be that the unit experienced a spike, and that was enough to punch through the very thin enamelled wire insulation of the choke.
The irony being that if the heatsink was actually grounded (i.e. connected to neutral or earth) then it would have failed safe. With a non polarised input connector there would be a 50/50 chance of the heatsink being live.
In my experience they do almost always connect the heatsink to something appropriate, either to stop it radiating RF or so that they don't need to isolate it from the device that's being cooled.
Pro tip: The Surface Pros work with USB PD supplies of sufficient wattage, and you can buy Type-C to Surface cables off Amazon. I unfortunately bought a couple of these junk Chinesium dealies before I discovered this fact. Both were prone to sparking on the DC side when you plugged them in. Due to poor grounding, they also cause issues where the Type Cover track pad works intermittently. One had really bad coil whine, the other got quite warm even though it was the correct wattage. Unfortunately, the charge ends always go on all Surface supplies due to the design completely lacking any strain relief. The cable is permanently attached to the brick, and Microsoft wants a fortune (seriously, more than even Apple charges) for an official replacement. With the USB route, you just grab a good quality GaN supply (I got an 65w Anker one) and replace the cables as they wear out. Don't bother with any other third party Surface chargers. I'm pretty sure every one on Amazon is garbage, and a ticking time bomb.
Yes, but the point is also valid: starting from the Pro 7, it is possible to use a USB-C power supply. 45W is enough, 65W is ideal. I use a name brand USB-C charger for my phone, surface, and headphones. 35€ for a decent universal charger is hard to beat.
Yep, I got a USB-C to Surface adapter, and I have a 65W Minix brand GaN USB-C tiny thing, works for my wife's 2018 Surface Pro. I also managed to hack apart the original supply Surface connector and the ground wire had completely sheared at the input to the connector, was able to fix it and hold it all together with a bit of heatshrink, so we have both options (now the charging/ connection light is shining out the end as I wasn't able to get it reassembled with the little perspex light pipe). Those GaN chargers are very nice! So much smaller (thus more efficient) than the original Surface supply.
Had a similar one, though this was caused by the genuine power supply capacitors going bad. 12V supply went out of regulation, all the way to 50V, and killed the equipment it was connected to instead. Fixed the PSU temporarily and yes, other side deader than a doornail. Kind of expensive for the hotel though, it was the master unit for their door cards, and a pretty penny to replace, all because they cheaped out on both power supply, and a transient suppressor diode on the input to the machine as well.
That could have been the feedback circuit failing. I've seen a precision reference circuit backed up with a slightly higher zener diode as a precaution. But if the opto isolator fails then the voltage will float to the unregulated level.
@@bigclivedotcom No, feedback was well damped, so the spikes charged up the output capacitors to around 50V in spikes, before the feedback loop shut it down again. IIRC the new programmer was around 25 thousand pounds to rush order and airfreight in. For the hotel about 2 days profit in peak season. Famous hotel, even the cat has it's own Instagram and Facebook page.
@@quantumleap359 I meant the monitor when I mentioned the fuse. Sorry I assumed that was obvious as it was replying to a comment asking about repairing the monitor.
@@stevetobias4890 just wild guess, the power went probably over the signal board to ground. There should not be a major fuse on the signal board so, with luck, only the signal board looks like the charger, with bad luck it also taken the display control unit with it and the display itself but probably the backlight and PSU from the Monitor are fine XD
@@MalownMcOwnage Clive said explicitly that the current went up the ground line, not the power line, so presumably it also went up the ground connection to the monitor? You'd expect the ground on the tablet to be attached to the monitor ground via the cable, after all.
Mr. Chin Magoo oversaw the final approval and totally missed this flaw. Good detective work by our Clive, whom has been at the top of his game, providing us with his electronic prowess and even managed to include "knock one out" "schmoo" and "bang" all in one episode. Well done!
I pat test thousands items a year. It never ceases to amaze me when people have a £1000 phone, yet buy the cheapest nastiest power adaptor, often from amazon.
“Price per unit adjusted to reflect expected defect rate per lot” -seen on multiple types of electronic lots advertised for US import (then the importer does not QC, marks up anyway)
@@wisico640 It's an insulator indeed, but not as strong of an insulator as a one-two punch of plastic AND an air gap. It's still got a tiny bit of thermal conductivity, while stale air locked into a gap has pretty much zero.
@@wisico640 Insulation in this case isn't the intent. Heat sink compound is intended to convey heat to the outside, usually via a metal case (!!) or larger metal plate that can effectively radiate the heat away. I doubt plastic is a great heat dissipator.
Am I the only one that's disappointed when electronics don't fail fantastically? Exploding faults are ever so much easier to locate. Plus, you get a show for the cost of the damage, which is better than nothing at all. Thanks for the analysis of this POSU! As a side note, I once worked for a small manufacturer who had entered negotiations with a Chinese manufacturer for pre-made power supplies, when he gave the list of required certifications, he was assured that they could print "any sticker you want". Insistence that the power supplies actually had to meet the certifications got nowhere, a different supplier was found.
I’ve seen an unusually high number of aftermarket Surface power supplies fail catastrophically; not just one particular design or manufacturer. We ultimately had to send out an advisory to our users banning these supplies. Often in such cases the Surface is irreparably damaged. I’ve examined a few seemingly from different manufacturers and implementations. In most cases tracking and/or arc-over is apparent, but the exact cause has varied. Signs that the heat sinking material itself provided a path thru isolation has been noted but not in all cases. The only common factor I’ve noted is all such failures have been 3rd party reproductions that attempt to mimic the small compact form factor of the OEM power supply. None of the failures have been aftermarket Surface power supplies with a more typical brick implementation. Regardless of how nice the case finish might be (some have been almost indistinguishable from the OEM model down to the texturized surface finish, regardless) the internals have been sloppily assembled. The OEM form factors is rather compact for a given wattage and I suspect many 3rd party manufactures are unable, unaware or uninterested in ensuing the required implementation and tolerances required of the form factor. Given how difficult this design is to open and inspect I just say stay away from them.
Steve Dubin. Most of these products are Double Insulated hence the two pin plugs. Properly designed double insulated equipment can be considered as safe as class 1 equipment, which has a protective earthing system.
When I was looking for a new PSU for my Mac laptop the choices were £40 for a third party part or £85 for a genuine apple part. Perusing the reviews of the third party supply, at least three on the first page basically said "Smoked my laptop". The additional £50-ish seemed like a saving against >£1000 for a new laptop. Lower cost isn't always cheaper.
i've seen much worse, usb charger with no mains fuse except wires to the pins, and standard grade cap from live to output instead of a proper class y2, or 2kv dc type (1kv was fitted)
@@jaycee1980 Hi, you don't necessarily need to provide additional sheet insulation if the design is such that you can guarantee to provide sufficient creepage and clearance distances between primary and secondary circuits.
@@brucepickess8097 indeed, but in stuff like this that gets thrown about and the potential for stuff to shake loose is there - a sheet of insulation is a guarantee :)
You can do that and still be safe - many laptop power supplies do. However the heatsink is not connected to anything, whereas this one was connected to the "ground" of the line side. Problem with this is that you can't guarantee thats neutral - especially in this design where they are using an unpolarised "figure 8" plug.
Like others have mentioned: that's a replacement AC adapter... very possibly a very cheap one at that... I did have some Surface devices die on me (or rather my customers) but usually it's the device or battery in it. Not the peripherals. Tablet go BOOM!
Annoyingly "cheap" doesn't seem to matter either. I had one that was like $50 for a 12V 10A power supply replacement on an electric TEC cooler calling for 12V ~5A and blew up rather spectacularly (and eliminating a chunk of the PCB and decap-ing some chips inside). After that I got the cheapest $15 one I could find, which has performed flawlessly since.
I have opened up some dodgy power supplies like this. In my case it was just a generic 24V supply, but it had that same design issue of heatsinks which run between primary and secondary, and I had wondered if that was an issue at the time. Turns out yes, yes very much so. One bone-headed design choice defeats all the separation instantly.
Some power supplies have the inductors sheathed in thick walled heatshrink tubing, although I think it is more to reduce vibrations than to increase electrical insulation it will do both functions and also increase the protection against rubbing.
I do remember laptop transformers 10-15 years back seemed to get very hot and never seemed to last more than a few years, though they all failed safe for me without damaging equipment. There were cheap replacements from ebay around, but they failed too after a bit. They are far better now, so I guess manufacturers have improved things over the years. One thing I also noticed then was that simple electrical supply fittings of laptops seemed quite poorly made in the early days too, power lead plugs, wire connectors and sockets for example.
Personally I don't like the idea of a power adapter without an earth connection to the mains power outlet. A LOT of PSUs back then only had the two prong cassette tape power lead. Not good in my opinion.
My first laptop back in the days of dial-up internet was terrifyingly hot EVERYWHERE. All it was all supplied by a Famous High Street Electrical Chain, but it was all so hot you could fry eggs on it. Transformer, the lot. I don’t know about such stuff, so not sure if the early equipment was prone to this. Anyway… I am going to try and teach my self to check stuff out.
There's some "good" aspects on it (like the isolation notch under the opto-isolator) which makes me wonder if they might have copied something else and then down-costed all the components to produce a cheap clone. And perhaps one of the replacements was to switch from an expensive and smaller surface mounted coil (not going to touch the heat sink) with a big and cheap wire-wound one. Or dropped the isolation that the original might have had. I'm wondering if they also replaced a (better) metal-case transistor with a plastic case one, *if* the metal case transistor had negative main voltage on the case that might explain why the shield was connected to that, why not just anchor it in a nearby track that has the same potential. Just speculation and without examining the PCB in detail it's impossible to know if that is the case, even with the PCB it may not be possible to be sure if that's how they go there.
I love the heat sink paste on the plastic case. Really useful! Dominic Littlewood did a TV article about a young boy found dead in his bedroom after being electrocuted with a cheap power supply. Still eBay continue to sell this shit.
@@benbaselet2026 Ebay is great, but it's flooded with unregulated Chinese garbage and that's the shit you need to avoid. Basically you have to be savvy to navigate and read through some of the marketing the Chinese use to make sure it's a Genuine one you're gonna get or it's a knock off. Usually they say "Unbranded" in the Description and "For XXXX" X= Device Model or Brand" rather than just "Brand name"
@@AeRiaL_ ebay is just as flooded with cheap crap as amazon is. but amazon got its own fake review center on top to trick people even better. IMO they can just shut down amazon and nothing was lost. one can shop online in actual shops with actual human shipping it. not the amazon borg-type item collectors running around the stock for their hourly penny so they don't get thrown out their 1-room apartment.
Usually when I take apart power bricks like that from laptops etc. those large metal heatsinks are well wrapped with a couple of layers of that yellow transformer tape to prevent stuff rubbing and shorting on them.
@@norliasmith It's not kapton tape, that's different color and transparent. I mean the yellow stuf you find in transformers. I'm sure it has a proper name but I always see it referred to as transformer tape.
Cheapest possible devise to use with your expensive stuff. Coolest thing was a laptop customer brought in that was struck by lightning it was plugged into the dsl modem with a lan cable
I felt like I was watching a good detective movie! I've been doing failure analysis on electronics and mechanical systems for a good while, but that one would have had me stumped beyond seeing the arc-strike between the inductor and the heatsink. I probably would have just figured the power transistor had a meltdown and caused the burnt area due to direct short between the mains in. 😳
I had a customer hand me a dell laptop to fix once, which clearly had a fakey power adapter, they had copied the dell adapter casing almost to a tea but the fakey adapter weighed a fair bit less than a genuine one. Also the fakey would not charge the battery as the genuine Dell adapter had a 3rd wire in the middle pin, presumably for serial comms, so that the laptop knew the size of the adapter connected.
I got an old Dell laptop with one of those adapters and it would charge the battery or run the computer but not both at the same time. Under load the identification chip couldn't be read, presumably due to excess noise on the output. Upon opening the adapter I found the primary side capacitor had went bad (to the point of one lead falling off). As if it weren't obviously crap from looking at the outside, the AC ground connection wasn't soldered properly. I ended up taking the output connector and ID chip from the fake adapter and attached them to a decent other-brand power supply and it worked fine.
My thoughts exactly because sometimes fake stuff or electrical gear made in China is often poor quality and doesn't meet safety standards. It's best policy sometimes to pay a little extra an get something that's safe an lasts longer. I have heard of batteries and chargers an power supplies catching fire when in use due to poor quality components and design.
I agree with things just getting by, you cant think of everything every time. But, I don't think it takes a electrical engineer to know that when you intentionally isolate one side of the board from the other, you probably shouldn't go laying a big piece of metal over said isolation.
Hahaha! About a year before I left my "large company IT job" we started getting surface tablets for people. I left a little over the 1 year mark and batteries were already starting to puff. I was so angry because those stupid computers also came with a "ship it off to have repaired" clause and we could no longer take devices apart and repair them. About a month before I left they signed an agreement to get those 1st generation glued together surface laptops. That verified my decision to leave.... No more repair, throw it all away.
@@GameBacardi Hi, with a properly designed OEM charger, leaving the charger connected 24/7 to the device should not cause any deterioration to the battery in terms of physical deformity.
I like these forensic investigations. I refer to these entertaining videos as "Why things went bang" video series. They're like horror movies, because it's so real that some innocent, cheaply manufactured item might hurt, kill or burn your house down. And we just keep blindly accepting them as "normal" without doing anything as consumers to save ourselves.
I have a few of these power supplies, all of a smaller power capacity. I have taken some of them apart, and even when they look a little different on the outside, the components are the same layout as in this one. None of mine have ever burned, and the difference is in the smaller one that I have, the heat sink, and the inductor, are both small enough, that they can't touch each other. One thing I do notice is that on mine, there is a glob of that white "shmoo" on the inductor. I don't know if they were trying to keep it insulated from the heat sink, or if it was to keep it from vibrating. Either way, I am glad to know about this fault. I will keep an eye open for this in the future.
Darrick steele. The white "shmoo" compound is normally used to provide mechanical stability to components. As far as I'm aware the compound has no insulative properties.
I look after alot of desktop IT, and some of that is Surface Pros. We have had people loose PSU's so we got a load of "Replacement Surface Chargers" from a very well known IT reseller in the UK that sells to the trade. In no time at all staff were complaining they were feeling a buzzing when touching their MS Surface's. I tested one with my Fluke and sure enough i was seeing about 80v AC on the outer case !. So we issued an email to all staff to throw these chargers in the bin. Thus we got some genuine Microsoft ones.
That's common. It's capacitive coupling between winding layers and through the class Y RF suppression capacitor. It's only about 100uA, but with 10Mohm input impedance, a meter will show a highish voltage. It's also enough to give a tingle from metal surfaces. You'll find the same with most ungrounded power supplies including Apples.
The most honest comment I will ever put is that I watch RUclips a lot on my Xbox One, and which is an unsigned account the algorithm gives me _tonnes_ of content which I would want to or not want to watch, and lo one day I came across yours just watching you surgical commentary and the "Oh! Ok!" Surprised comment when you find out how bad, bad electronics are and the low quality cheap Chinese stuff too! Brilliant content as always!
I don't know if it's practical after all the damage, but it might be an interesting video to reverse engineer that power supply and then show on the schematic what shorted to the inductor and why that made it go bang.
I just watched this video with an identical supply powering a Surface pro 4. Its the third supply I'm using, both an original microsoft one and another knockoff one have blown up with a loud smelly pop in the last 12 months (which I've put down to excess heat as these computers draw quite a lot of power). My better half also complained of constant electric shocks using this current one, though it didn't seem to put out more than a mA or two when measured against mains earth. I'll tear mine apart now - if the inductor and heatsink are too close I'll modify mine and report back on here as another bad one. Big thanks again, another awesome video Clive :-)
This is why I never buy aftermarket power supplies, much prefer a used OEM one to one of these aftermarket units for exactly this reason. Of course there's no guaranty this wont happen, but seems much less likely something like that would be missed.
Seen far to many laptops with blown charge ic or worse totally dead fixing computers for years. Never buy this cheap Chinese crap. A power supply isnt something to mess with. Buy oem or high quality.
Thank you for the up. A relative too kept the cheap psu in a prebuilt medion pc, and fried his new at the time 1050 ti. being on tight budget, it was a deep burn. a expensive surface with a cheap psu is the cakes cherry. getting a good maybe gold psu will actually save you some quid in the long run considering those have better efficiency.
I plugged in the extension brick which acts as the psu and adds more ports to my work laptop. It gave my monitor a warning of over voltage. Brand new from microsofts bussiness store.
The advantage of the brand name is that you get to send it back under warranty. Chinese junk, not so much. (Amazon might refund your money, but your fried equipment is your loss.)
I really don't understand why these Chinese clone makes go through all of the effort of designing these things and then just get sloppy randomly with the actual manufacturing. I see this all the time with your teardowns. They're so close to making something perfectly serviceable and they just get so sloppy with the components. Before I watched your channel I enjoyed taking things apart just to look at them. Now that I've been subscribed to your channel for a few years I take things apart just to see if I can make tiny modifications to make these devices much more secure without much effort. Thank you, as always.
The thing is it has never been just the Chinese, it is every company where accountants are allowed to interfere with what the designer specified, just to save a couple of pennies. Rover Cars, just before their demise, used cheap components to cut the cost by a couple of pounds per vehicle. What were beautifully designed cars were subsequently plagued with problems. I imagine it made the designers cry. The warranty claims and damage to their reputation finally pushed them under.
Its because the workers are complete lazy bastards even if making it better would cost nothing or doesn't take extra time. Pushing the inductor away from the heatsink would take 0.01 of second. They do the absolute bare minimum just so it works. No thought given to safety.
I don't think they know what they're doing really. They get some sort of decent successful design and then they copy it and they make mistakes on top of it. True expertise costs money. Maybe once in a blue moon they even hire a specialist to design a thing, and then over the course of time it... morphs due to manufacturing branch just implementing changes and them not being validated. There's a wild mix of things out there which some get reasonably close to getting it right, and those that are complete garbage and which cannot be helped. That being said i think that's a phase. I think these companies go two ways, either they eventually die, or they eventually learn to do it properly and become a supplier for a number of tier 2 brands, with an occasional tier 1 brand in the mix, they go legit. The ones who have gone legit are then just not the subject of these sorts of teardowns, neither for the "cheapest on Ali" hauls, because obviously the stuff is anything but cheapest then nor the explosion post-mortems with funny spelling.
This is what surprise me too. Just like you say they go through the effort of making things but the end product is so shoddy. If they only put in slightly more effort they would be making top tier things. Something as simple as just the written English on the product. Then again, what isn't made in China these days? Even a good brand can fail.
Brilliant find! When I’m instructing my tech’s on my learned catastrophic failure troubleshooting techniques. I teach them first, that a comprehensive visual inspection is going to lead them to the issue 99.9% of the time.
Hopefully it took the stupid horrid tablet with it! (Enterprise IT guy who has to manage a fleet of these overpriced things here, if you can’t guess 😂😂)
In my industry we carry out physical qualification tests which includes vibration, specifically for issues like this. As the PSU was apparently CE marked, they should have done the same (but presumably that was fake). My suspicion is that whoever made the heatsink made it slightly oversize or the hole for fixing it to the FET was drilled in slightly the wrong place. For insulation (between the fouling part and the heatsink) they would have to use something like AshLam (essentially a thin, flexible piece of GRP similar to PCB material) as Kapton would eventually wear or creep through.
i find that even OEM chargers give zaps and blow up. Samsung, Apple, they all make this trash too. It's just people have a weird bias that the more expensive something is, the more of a HERO they are. What a clowny world.
@@wisico640 nope, straight out of the OEM box straight out of the OEM shop. The charger that comes with the iPhone (the old ones when they had chargers), and right out of the unopened box of a scamsung laptop. Touch the metal by the keyboard and you feel a tingle. A good 60VAC to ground at 0.01A or something.
@@dimitar4y happenend to me once, with a dodgy ATX computer PSU, plugged in dodgy electric work / bad wired plug in a damp basement. What you experienced is in no way normal :/
@@wisico640 it's "normal" in the new world order. You will own nothing and you will be happy, and you will be productive, and you will be paying 60% taxes.
Thank you, that was a great diagnosis. I love it when you do this. We had a similar experience with pinched wires, passed all tests, then after a while, the insulation gives way and creates a ground path. In our case, it just tripped circuit breakers.
Thanx for showing. I also recognize a general design flaw in this unit. They made the gaps in the PCB and seperation of the low and high voltage side useless by putting the heatsinks over the entire length.
This is why I always go with an oem psu as it’s far less likely to be this way or at least take a cheap one apart to inspect it first if it is my only option.
The first thing I thought was like KiloSierraAlpha, that the inductor originally had adequate clearance from the heat sink but got dropped. Dropping it may have pushed the component into the heatsink and from there on it rubbed against the metal until it wore through the coating on the wire. There are multiple millions of economy products out there that perform satisfactorily every day. It's not because the item was a lot cheaper that it was cheap junk. If this company can build a power supply and sell it cheaply imagine how little it costs Microsoft to build theirs. Gouging is a huge problem with big companies. Thank God for the little guys who help keep prices reasonable.
lots of brands that make good psu's that aren't OEM. It's like almost any other product you buy that might need replacement parts. OEM is almost a sure bet that it's quality, but that doesn't mean other companies don't make good stuff too. You can buy cheap ass brake pads for you car that delaminate in month's, or good quality ones. You can also pay twice as much for oem parts from the dealer, but that doesn't mean they are any better than cheaper (but not cheap!) quality parts from another company.
The amount of times I’ve seen heatsinks bridge gaps of circuitboards is terrifying. Specifically name-brand-giant companies. It especially concerns me when the heatsinks on certain devices are naturally live and/or short by design.
Hi Big Clive, You are a very talented forensic electrical engineer! Here in the United States I'm sure you would have been hired to determine the reason for an electrical fault or fire by our court system. Or maybe you already do forensic electrical work for Great Britain? Your testimony could determine the outcome of a trial! Great videos! Thank you for all you do!
can you open an old 90s laptop power supply? I remember they used to be the size and weight of a literal brick in the early 90s and steadily got smaller and lighter over the years, but particularly in the last 10 years to now where they're maybe only a fifth the size and less than a tenth of the weight.
This is extremely useful to know and I thank you, especially because I have some young ones in my family and they've been watching this vid and are most grateful. Best regards -Wendi
often *WHY* inductors are usually heatshrinked in these types of switching power supplies.... and I don't think I've seen any conductive reaching across the isolation gap between the high and low power sides like that.
Hi Clive, the Heat-sink is connected to Bridge Negative to reduce the EMI produced by the Switching Mosfet capacitively coupled to the Heatsink(Ccase,Cinsulation) and preventing the Heatsink to act as an Antenna for that Switching Noise, It's common Practice to reduce EMI. But Clearly the Component Placing is bad.
It was turned into a mini plasma cutter that cut a notch in the aluminum. Besides, it even tells you will need to "Replace AC adapter" right on it. Who knew it would be immediately? 🤷♂️
I get the impression that the inductor forms part of a buck regulator for the USB socket. It never ceases to amaze me that people will spend hundreds of pounds on a phone or tablet, then buy a cheap and nasty power supply for it. As you've demonstrated many times, Clive, these supplies can destroy your equipment or even kill you. Please keep making these videos, Clive, people need to wake up to these death traps.
Nightmare scenario! It blew-out all their expensive equipment. The engineer probably never saw the physical product assembled after designing it on the computer, otherwise they would have been concerned with the proximity of that flimsy coil to that heatsink. When you're just looking at it on the computer all you see is "there is room between", and the sense of scale is different.
These "heat sinks" (in quote marks because having something like this in a completely closed plastic case with no ventilation is a bit pointless) are what came to my mind as the source of failure immediately. So many bad designed electronic devices out there it is scary...
To answer your question @6:08 of "How many of these are out there...", A LOT. I work in IT, and Surface Pros account for about half the staffs mobile computers. Against our advice, some teams buy these cheap replacements when needed to try and save some money. In the end, they end up having to replace the whole device. Spend the ~$90 on the charger to save ~$1000 on a new device, don't try to save $70 on the charger.
I had a similar (cheap replacement) power-adapter for a MacBook once on my bench. They used a shielded cable for the low voltage side. After some use the cable shielding could sneak back into the casing due to bad stress relief of the cable and eventually made contact to the (live) heatsink. The owner of the MacBook got quite an electric shock from the (then live) metal casing of the MacBook. Luckily the owner and the MacBook survived that incidence.
I'll admit I still use "questionable" supplies from time to time. Supplies that look good, but you still have that nagging doubt. As a workaround, I usually earth the low voltage negative. Treat it as a Class 1 appliance on both sides of the transformer.
That looks like the power supply board I pulled out of my Playstation 4 about a year ago. It let out the magic smoke while I was about an hour into the game that convinced me to buy a PS4 in the first place. Fortunately, it didn't take anything else out and was an easy fix.
It tried to warn him, the instructions on the back were clear. "replace ac adaptor"
That warning wasn't clear enough. It should have read *_Reprace_*_ AC adapter_ and that would have made the warning crystal clear then. 🤦♂
@@josephking6515 Reprace **this** AC adapter.
That's the best comment I have ever heard . . .
Oy hoi hoi lllllllmao
That's hilarious, thank you. 😊
"Temperature increase during use". Well, they weren't lying.
Thermal compound between metal and plastic. Would that really help?
Momentarily as hot as the sun...
It is normal that device explode.
"Device hot boom if use."
Yep can confirm those bricks would get stupid hot. Never felt safe to me.
I was immediately bothered with seeing something conductive right across the isolation… seems like an accident just begging to happen. The labeling on the outside is a definite red flag. Rather scary device.
I was going to ask about that. Is it not a bad design to allow anything conductive to bridge the isolation? Even the heatsink.
Pressure to design a small PSU whilst also cheaping out on the components.
If the PSU were more efficient it wouldn't have needed such a large heatsink in the first place.
@@felixokeefe if you were designing a PSU for best reliability, on the basis that it is going to be in a sealed plastic enclosure, you would have lots of sheet metal inside to efficiently spread the heat over as much of the box's surface as possible and to therefore minimise the existence of hot spots. Keep the components uniformly cool, have them last longer.
So there is some merit to what was done here - it just wasn't done right.
And the small blob of white goo connecting the metal to the plastic case is a bad joke - shows that they hadn't thought it through or didn't have proper communication between the designers and the manufacturers, or the manufacturers just didn't understand or care how to do it right.
@@Rich-on6fe you make some good points.
I've seen similar style PSUs where the heatsinks have been wrapped in Kapton tape. Presumably to protect against this type of failure mode.
I have a similar power supply, but the sharp edges of the heatsink are taped over and the inductor is protected by shrink tubing.
@@flightisallright Sounds like they discovered (the hard way) the same problem that Clive identified here.
Poor design. They took the trouble isolating the high & low sides of the PS on the PCB (including notching under the optoisolator), but then bridged the isolation gap with the heat sink.
Yeah. I wonder if a different person designed the heatsink. Maybe in response to an earlier design getting too hot?
Doesn't look like a genuine Surface AC adaptor though. Just a shitty 'chinesium' copy with a LOT of cost cutting and shortcuts compared to the original ones. Its way larger than the original ones too, MS make some fantastic PSUs including in their consoles, this ain't one of them.
@@zybch It obviously isn't a real one.
@@zybch I doubt MS OEM their PSUs. For something so jelly bean its generally woth getting a general design from some true experts, like TDK lamda.
Probably another revision. Just look at how the other corner is cut diagonally, which might have been better for the faulty corner rather than the one with the USB port (which isn't even in the cut off part).
My “cheap replacement power supply” story: I was working with an audio testing company and we spent hours trying to figure out where a certain noise spike was coming from in our device. A lot of audio and cellular test equipment was in use, and all of it was controlled by a laptop computer. Out of frustration, I unplugged the laptop power supply and when we reran the test the noise spike was gone. The power supply turned out to be a cheap aftermarket one. We tossed it in the trash and got a genuine one from another computer and had no more troubles.
I bet there was a CE logo on there too.
@@dorbie Not all CE marks are equal… There is a diference in letter spacing between "true CE" and "China Export CE"
@@FalkonNightsdale Except even legit stuff has quite often got it wrong.. I've found several definitely 100% legit items with bad CE marks.
@@FalkonNightsdale Total coincidence I'm sure 😀
@@silverdragonslair They srls need to change CE to somethink outher like European Certificate of Conformity (ECC in short). Because be real here China do this special and for most of consumers it's hard to spot a difrence. And as you see even genuine europen parts and certyficates print this wrong...
That heatsink plate totally compromises the separation. What on earth were they thinking?
Or on neutral, for that matter!
They were probably so focused on the separation on the circuit board (which they did pretty well), that they completely missed it.
It can have been a simple error in producing and lacking of QC.
For example there is a cutout on the plate that makes little sense right now but if you turn the plate around, there is some distance between high and low voltage parts.
So, maybe someone was just putting the plates in the cutter the wrong way round and cut of on the other side, having no knowledge of where it was going to be used.
Then placed on the boards in the cases and shipped without further good checks.
Of course works when it works untill boom.
By the way, Clive, was the heatsink not soldered well on the board so it could move, only fixed with the screw on the transistor-package?
Maybe engineers in a different department modified the design
@@elvinhaak That heatsink covers all the components so if any checks were made on the board they would have to be done before the heatsink was attached, there was nothing holding it apart from the transistor either and it also looks like the plate was cut wrong, it appears they were hoping the heat transfer paste would be enough to hold the plate in place by sticking it to the plastic case and prevent it moving around too much !
There are many issues that should be picked up by quality control but they don't care about quality, they only care about sales.
As a designer involved in designing equipment to meet the requirements of the International Standards marked on the case, it is totally obvious that even if the power supply met those requirements when it was submitted for testing, it certainly doesn't in its current form.
Whether or not that is the case, and I doubt that it was ever submitted for testing, it means that ALL the Approval Markings are either invalid or fake or both.
The issue of rampant deception, safety issues and poor quality control is not just overly common in Chinese Products, it's typical.
Just less so in products supplied with "Branded Products".
CAVEAT EMPTOR!
You mean that there's a chance that even a reputable brand that outsources manufacturing of a product to a Chinese OEM may actually be getting a fire hazard that doesn't follow all regulations?
They don`t need to go trough all the testing if its based on a similar design that is tested or do they? I'm not familiar with it
In Germany they did some mass testing of DC adaptors, quite a lot were completely unable to meet the power requirements marked on the case. Probably over 80%. So it's wise to buy something like 2.5A if you need 1A.
@@a4andrei The difference is a big brand will carry out testing prior to inclusion of the unit in their product. Load testing, vibration testing, temperature chamber testing.
@@chinchan9 I think the issue is that even if they submit a compliant design for testing/certification, they then progressively change it to save cost, without ever resubmitting it for testing and certification. Unless you have your own eyes on the ground at all times (like large companies like Apple, HP, etc. do), Chinese companies will take liberties to reduce cost, hoping their client won’t notice. When the client does notice, they’ll undo the last change, but they’ll continue trying new changes. (There’s a great book on this, “Poorly Made in China” that I recommend.)
For sure, there are Chinese companies (like Foxconn and Quanta) whose business model is based on _reliably_ high-quality, to-spec contract manufacturing. But it seems they’re the exception, not the rule.
Can we all take the time to appreciate the work this man is doing to educate and entertain us. Man thank you.
I bet he is dooing it for his own entertainement and just lets us participate in his hobby xD
Damn, i hope to see his x-ray again
@@Em.P14 that's what makes big Clive's videos so good to me. He's not being all crazy to try to capture our attention, he's simply incredibly interesting on his own and just let's us tag along.
"Vibration during transit" is also my guess. That toroid was not secured. I've repaired many Anton Bauer chargers for pro camcorders which had an identical choke. Luckily, when it broke off it didn't short anything- it just stopped working. A little solder and a lot of hot melt glue fixed them.
Yeah, it needed some hot snot
FYI, I’d use proper electronics silicone (like Dow Corning 744), since many hot-melt glues can just fail, releasing entirely.
@@tookitogo - difficult with existing products, but with that type of inductor, I prefer a nylon cable tie holding it to the board via holes purposely made in the board.
that is Sad Not even the pro gear is safe from poor designs and cheap parts .
@@richardbrobeck2384 - I service video equipment and it’s much more at risk from Photogs lol
Yet another hard learned lesson on not to use cheap clone power supplies with expensive equipment. There is a reason why the genuine replacement power supply costs more.
Same thing with batteries and tools that can pull current. Seen a coworker's tool catch fire from Ali-express deals that are "cheaper".
@@Goabnb94 Ali Express keeps trying to sell me silencers, I have no idea why. Weird company.
& there are also good replacements out there. Don't cheap out too much tho
The reason genuine psu's cost more is greed.
As this shows just a single component placement was the issue so there are plenty of cheap psu you can buy that are great.
@@jasonwilliam2125 agreed, just get a electrical engineering degree already.
I always open cheap PSU's and Chinese electronics to add insulation/upgrade wires and prevent problems.
I have an 800W PSU i bought for $23CAD including shipping thats been working great for over 2 years now.
Would be great to see the inside of a genuine adapter and a comparison with this one.
Lenovo Thinkpad chargers have lots of them.
My surface laptop one is heavy enough that i suspect it's potted.
@@qwertyasdf66 they're not potted just packed full of filtering, if i ever get another that's too bad to splice i should chop it open for youtube
@@Mister_Brown I ever wondered if they were! But I absolutely hate the original ones, they're terribly unreliable, 80% of those I have in my company stopped working and I'm not sure it was the DC cable
@@fabiosemino2214 I've had numerous Surfaces and none of their adapters have failed. I still use an original i5 Surface Pro from 9 or 10 years ago and it flies along with windows 11 (modified to not require the TMP of course). The worst I've seen brought into my repair shop for fixing are users treating stuff badly and the cable being kinked and frayed to the point of internal shorting. Pretty much and device marketed for its portability is going to see some really bad user habits with the cables.
1:00 No you read that wrong. It's not CALLED "Replace AC adaptor", it's TELLING you to replace the AC adaptor instead of using it! :-D
Cheap Chinese stuff gets it all wrong. Should read "Replace AC adaptor, laptop and monitor".
As a "retired" EE, I am reminded of the trinity of production. Cheap, fast, good... pick two. This device was obviously had a rushed design to sell at a low price. Like most cheap Chinese crap.
That's the cap theorem of ee (consistency, availability, partition tolerance - pick two)
Cheap, fast, good... pick *at most* two ;)
We had the exact same problem (with much less injurious outcome as we had e fuses) at my former workplace.
The "fix", which was more of a workaround was to put heatshrink around the whole inductor, which worked of course.
A virgin board was fine, but stick it in a container and ship it half way around the earth, yeah, that inductor moved.
Bit crap really.
They did a good job isolating low voltage from mains, then completely violated it with the heat sink/shield. Just simply dropping the PSU might have made the inductor touch heatsink.
Or the heatsink getting hot and malforming
Grounding that heatsink was the BIG design fault. Also another thing I notice is there is no MOV or spark gaps in there to deal with any sort of mains spikes. It could be that the unit experienced a spike, and that was enough to punch through the very thin enamelled wire insulation of the choke.
grounded for emc compliance? The switching mosfet is on the heatsink, isolated, but there's still quite some capacitive coupling.
The irony being that if the heatsink was actually grounded (i.e. connected to neutral or earth) then it would have failed safe. With a non polarised input connector there would be a 50/50 chance of the heatsink being live.
In my experience they do almost always connect the heatsink to something appropriate, either to stop it radiating RF or so that they don't need to isolate it from the device that's being cooled.
@@victortitov1740 not 'grounded' but rectified mains negative , big difference
the heatsink wasnt grounded, thats the problem, its rectified mains negative, -350v ish peak to earth each time on one half cycle,
Pro tip: The Surface Pros work with USB PD supplies of sufficient wattage, and you can buy Type-C to Surface cables off Amazon. I unfortunately bought a couple of these junk Chinesium dealies before I discovered this fact. Both were prone to sparking on the DC side when you plugged them in. Due to poor grounding, they also cause issues where the Type Cover track pad works intermittently. One had really bad coil whine, the other got quite warm even though it was the correct wattage. Unfortunately, the charge ends always go on all Surface supplies due to the design completely lacking any strain relief. The cable is permanently attached to the brick, and Microsoft wants a fortune (seriously, more than even Apple charges) for an official replacement. With the USB route, you just grab a good quality GaN supply (I got an 65w Anker one) and replace the cables as they wear out. Don't bother with any other third party Surface chargers. I'm pretty sure every one on Amazon is garbage, and a ticking time bomb.
Lots of the older Surface models like my mom's Surface Pro 5 don't have USB-C tho. I think they first added USB C on the Surface Pro 7
@@MrFastFox666 He's referring to the Surface port.
Yes, but the point is also valid: starting from the Pro 7, it is possible to use a USB-C power supply. 45W is enough, 65W is ideal. I use a name brand USB-C charger for my phone, surface, and headphones. 35€ for a decent universal charger is hard to beat.
@@MrFastFox666 You can buy an adaptor
Yep, I got a USB-C to Surface adapter, and I have a 65W Minix brand GaN USB-C tiny thing, works for my wife's 2018 Surface Pro. I also managed to hack apart the original supply Surface connector and the ground wire had completely sheared at the input to the connector, was able to fix it and hold it all together with a bit of heatshrink, so we have both options (now the charging/ connection light is shining out the end as I wasn't able to get it reassembled with the little perspex light pipe). Those GaN chargers are very nice! So much smaller (thus more efficient) than the original Surface supply.
Had a similar one, though this was caused by the genuine power supply capacitors going bad. 12V supply went out of regulation, all the way to 50V, and killed the equipment it was connected to instead. Fixed the PSU temporarily and yes, other side deader than a doornail. Kind of expensive for the hotel though, it was the master unit for their door cards, and a pretty penny to replace, all because they cheaped out on both power supply, and a transient suppressor diode on the input to the machine as well.
That could have been the feedback circuit failing. I've seen a precision reference circuit backed up with a slightly higher zener diode as a precaution. But if the opto isolator fails then the voltage will float to the unregulated level.
@@bigclivedotcom No, feedback was well damped, so the spikes charged up the output capacitors to around 50V in spikes, before the feedback loop shut it down again. IIRC the new programmer was around 25 thousand pounds to rush order and airfreight in. For the hotel about 2 days profit in peak season. Famous hotel, even the cat has it's own Instagram and Facebook page.
Sounds like what the Atari Lynx does when its MOSFET goes bad
I'd love to see a look inside said surface and monitor too, see what died and if it's repairable
It should have had a fuse on the power input side.
I seriously doubt economical repair would be feasible. It probably did widespread damage to the Surface. Don't know about the monitor.
@@quantumleap359 I meant the monitor when I mentioned the fuse. Sorry I assumed that was obvious as it was replying to a comment asking about repairing the monitor.
@@stevetobias4890 just wild guess, the power went probably over the signal board to ground. There should not be a major fuse on the signal board so, with luck, only the signal board looks like the charger, with bad luck it also taken the display control unit with it and the display itself but probably the backlight and PSU from the Monitor are fine XD
@@MalownMcOwnage Clive said explicitly that the current went up the ground line, not the power line, so presumably it also went up the ground connection to the monitor? You'd expect the ground on the tablet to be attached to the monitor ground via the cable, after all.
Mr. Chin Magoo oversaw the final approval and totally missed this flaw. Good detective work by our Clive, whom has been at the top of his game, providing us with his electronic prowess and even managed to include "knock one out" "schmoo" and "bang" all in one episode. Well done!
I pat test thousands items a year. It never ceases to amaze me when people have a £1000 phone, yet buy the cheapest nastiest power adaptor, often from amazon.
Do you test between the input and output?
unit: _overheats and blows up_
manufacturer: *that's normal*
"That's a feature"
“Price per unit adjusted to reflect expected defect rate per lot” -seen on multiple types of electronic lots advertised for US import (then the importer does not QC, marks up anyway)
Says so right on the tin.
@@Caretak007 yes
The thermal paste coupling the heatsink to the plastic shell is odd, I wonder if they were desperate to fix an overheating issue?
That is normal for laptop style adapters. They usually have quite a bit more of it in there normally.
Isn't the plastic case a good insulator?
@@wisico640 It's an insulator indeed, but not as strong of an insulator as a one-two punch of plastic AND an air gap. It's still got a tiny bit of thermal conductivity, while stale air locked into a gap has pretty much zero.
@@wisico640 Insulation in this case isn't the intent. Heat sink compound is intended to convey heat to the outside, usually via a metal case (!!) or larger metal plate that can effectively radiate the heat away. I doubt plastic is a great heat dissipator.
Am I the only one that's disappointed when electronics don't fail fantastically? Exploding faults are ever so much easier to locate. Plus, you get a show for the cost of the damage, which is better than nothing at all. Thanks for the analysis of this POSU!
As a side note, I once worked for a small manufacturer who had entered negotiations with a Chinese manufacturer for pre-made power supplies, when he gave the list of required certifications, he was assured that they could print "any sticker you want". Insistence that the power supplies actually had to meet the certifications got nowhere, a different supplier was found.
That needs to be reported to trading standards. It is potentially lethal.
I’ve seen an unusually high number of aftermarket Surface power supplies fail catastrophically; not just one particular design or manufacturer. We ultimately had to send out an advisory to our users banning these supplies.
Often in such cases the Surface is irreparably damaged. I’ve examined a few seemingly from different manufacturers and implementations. In most cases tracking and/or arc-over is apparent, but the exact cause has varied. Signs that the heat sinking material itself provided a path thru isolation has been noted but not in all cases. The only common factor I’ve noted is all such failures have been 3rd party reproductions that attempt to mimic the small compact form factor of the OEM power supply. None of the failures have been aftermarket Surface power supplies with a more typical brick implementation. Regardless of how nice the case finish might be (some have been almost indistinguishable from the OEM model down to the texturized surface finish, regardless) the internals have been sloppily assembled. The OEM form factors is rather compact for a given wattage and I suspect many 3rd party manufactures are unable, unaware or uninterested in ensuing the required implementation and tolerances required of the form factor. Given how difficult this design is to open and inspect I just say stay away from them.
It might have helped if it had has a protective earth - notice it's a two pin connector. Love the diagnosis Clive, not an easy one to work out.
The OEM chargers are all 2 pronged as well
But they also usually designed better // more precisely
Steve Dubin. Most of these products are Double Insulated hence the two pin plugs. Properly designed double insulated equipment can be considered as safe as class 1 equipment, which has a protective earthing system.
When I was looking for a new PSU for my Mac laptop the choices were £40 for a third party part or £85 for a genuine apple part. Perusing the reviews of the third party supply, at least three on the first page basically said "Smoked my laptop". The additional £50-ish seemed like a saving against >£1000 for a new laptop.
Lower cost isn't always cheaper.
Another reason to be skeptical of cheapie power supplies. I've learned a lot from these post-mortem teardowns.
apart from that clearance issue, it looks fairly good, if they had just made the heatsink 10mm shorter that end, it would have been ok
i've seen much worse, usb charger with no mains fuse except wires to the pins, and standard grade cap from live to output instead of a proper class y2, or 2kv dc type (1kv was fitted)
There doesn't appear to be much clearance between the top of the output caps and the underside of the heatsink.
typically there should be a sheet of insulation between them.. of course, there wasn't here...
@@jaycee1980 Hi, you don't necessarily need to provide additional sheet insulation if the design is such that you can guarantee to provide sufficient creepage and clearance distances between primary and secondary circuits.
@@brucepickess8097 indeed, but in stuff like this that gets thrown about and the potential for stuff to shake loose is there - a sheet of insulation is a guarantee :)
That is 'shocking' Why have any separation/isolation on the board when you are going to put two big strips of metal one end to the other?
You can do that and still be safe - many laptop power supplies do. However the heatsink is not connected to anything, whereas this one was connected to the "ground" of the line side. Problem with this is that you can't guarantee thats neutral - especially in this design where they are using an unpolarised "figure 8" plug.
Like others have mentioned: that's a replacement AC adapter... very possibly a very cheap one at that... I did have some Surface devices die on me (or rather my customers) but usually it's the device or battery in it. Not the peripherals. Tablet go BOOM!
Nope that was a poor honest soul at the manufacturing line that was sending us a hidden message 'replace AC adapter'
As soon as I saw that I tought to myself "it was foreshadowing" 😂
Annoyingly "cheap" doesn't seem to matter either. I had one that was like $50 for a 12V 10A power supply replacement on an electric TEC cooler calling for 12V ~5A and blew up rather spectacularly (and eliminating a chunk of the PCB and decap-ing some chips inside). After that I got the cheapest $15 one I could find, which has performed flawlessly since.
I have opened up some dodgy power supplies like this. In my case it was just a generic 24V supply, but it had that same design issue of heatsinks which run between primary and secondary, and I had wondered if that was an issue at the time. Turns out yes, yes very much so. One bone-headed design choice defeats all the separation instantly.
Gotta love the thermal coupling to the plastic case with heatsink compound. "Look, we tried!"
The case on all fully enclosed plastic enclosures are intended to radiate heat. The box is intended to get hot. The thermal compound is not useless.
Some power supplies have the inductors sheathed in thick walled heatshrink tubing, although I think it is more to reduce vibrations than to increase electrical insulation it will do both functions and also increase the protection against rubbing.
I do remember laptop transformers 10-15 years back seemed to get very hot and never seemed to last more than a few years, though they all failed safe for me without damaging equipment. There were cheap replacements from ebay around, but they failed too after a bit. They are far better now, so I guess manufacturers have improved things over the years. One thing I also noticed then was that simple electrical supply fittings of laptops seemed quite poorly made in the early days too, power lead plugs, wire connectors and sockets for example.
Personally I don't like the idea of a power adapter without an earth connection to the mains power outlet. A LOT of PSUs back then only had the two prong cassette tape power lead. Not good in my opinion.
My first laptop back in the days of dial-up internet was terrifyingly hot EVERYWHERE. All it was all supplied by a Famous High Street Electrical Chain, but it was all so hot you could fry eggs on it. Transformer, the lot. I don’t know about such stuff, so not sure if the early equipment was prone to this. Anyway… I am going to try and teach my self to check stuff out.
The fake looking UL stamp and splattering of other marks to try to assert it's safety kind of tells the whole story even without opening it
There's some "good" aspects on it (like the isolation notch under the opto-isolator) which makes me wonder if they might have copied something else and then down-costed all the components to produce a cheap clone.
And perhaps one of the replacements was to switch from an expensive and smaller surface mounted coil (not going to touch the heat sink) with a big and cheap wire-wound one. Or dropped the isolation that the original might have had.
I'm wondering if they also replaced a (better) metal-case transistor with a plastic case one, *if* the metal case transistor had negative main voltage on the case that might explain why the shield was connected to that, why not just anchor it in a nearby track that has the same potential.
Just speculation and without examining the PCB in detail it's impossible to know if that is the case, even with the PCB it may not be possible to be sure if that's how they go there.
I love the heat sink paste on the plastic case. Really useful! Dominic Littlewood did a TV article about a young boy found dead in his bedroom after being electrocuted with a cheap power supply. Still eBay continue to sell this shit.
Ebay just sells a market place for the actual scammers who sell this shit.
@@benbaselet2026 Ebay is great, but it's flooded with unregulated Chinese garbage and that's the shit you need to avoid. Basically you have to be savvy to navigate and read through some of the marketing the Chinese use to make sure it's a Genuine one you're gonna get or it's a knock off. Usually they say "Unbranded" in the Description and "For XXXX" X= Device Model or Brand" rather than just "Brand name"
eBay sells this shit because people keep buying it without thinking about how someone can make it for a fraction of of the price of a real one.
@@AeRiaL_ ebay is just as flooded with cheap crap as amazon is. but amazon got its own fake review center on top to trick people even better. IMO they can just shut down amazon and nothing was lost.
one can shop online in actual shops with actual human shipping it. not the amazon borg-type item collectors running around the stock for their hourly penny so they don't get thrown out their 1-room apartment.
I wouldn't put much faith in that other on line seller.
Usually when I take apart power bricks like that from laptops etc. those large metal heatsinks are well wrapped with a couple of layers of that yellow transformer tape to prevent stuff rubbing and shorting on them.
That would be kapton tape.
@@norliasmith It's not kapton tape, that's different color and transparent. I mean the yellow stuf you find in transformers. I'm sure it has a proper name but I always see it referred to as transformer tape.
... Thought something was missing!
Cheapest possible devise to use with your expensive stuff. Coolest thing was a laptop customer brought in that was struck by lightning it was plugged into the dsl modem with a lan cable
I felt like I was watching a good detective movie! I've been doing failure analysis on electronics and mechanical systems for a good while, but that one would have had me stumped beyond seeing the arc-strike between the inductor and the heatsink. I probably would have just figured the power transistor had a meltdown and caused the burnt area due to direct short between the mains in. 😳
I had a customer hand me a dell laptop to fix once, which clearly had a fakey power adapter, they had copied the dell adapter casing almost to a tea but the fakey adapter weighed a fair bit less than a genuine one. Also the fakey would not charge the battery as the genuine Dell adapter had a 3rd wire in the middle pin, presumably for serial comms, so that the laptop knew the size of the adapter connected.
I got an old Dell laptop with one of those adapters and it would charge the battery or run the computer but not both at the same time. Under load the identification chip couldn't be read, presumably due to excess noise on the output. Upon opening the adapter I found the primary side capacitor had went bad (to the point of one lead falling off). As if it weren't obviously crap from looking at the outside, the AC ground connection wasn't soldered properly.
I ended up taking the output connector and ID chip from the fake adapter and attached them to a decent other-brand power supply and it worked fine.
Thank you, I've used this video as a reminder to my team as to why we spend the extra to only buy genuine power supplies and batteries.
My thoughts exactly because sometimes fake stuff or electrical gear made in China is often poor quality and doesn't meet safety standards. It's best policy sometimes to pay a little extra an get something that's safe an lasts longer. I have heard of batteries and chargers an power supplies catching fire when in use due to poor quality components and design.
I’ve heard of big name power adapters being recalled for similar faults. I seem to remember having to swap adapters about 15 years ago.
Yep! The difference is that they take responsibility for it and recall them.
That was a fascinating tear down. Thanks for the video Clive. =]
I have one of these that just died! It didn't fry my Surface Pro 3, but it just stopped charging the thing. Damn. That could have been expensive.
I agree with things just getting by, you cant think of everything every time. But, I don't think it takes a electrical engineer to know that when you intentionally isolate one side of the board from the other, you probably shouldn't go laying a big piece of metal over said isolation.
I've had multiple Surface tablets with batteries doing balloon impressions with OEM chargers. Maybe not the most well designed devices.
Hahaha! About a year before I left my "large company IT job" we started getting surface tablets for people. I left a little over the 1 year mark and batteries were already starting to puff.
I was so angry because those stupid computers also came with a "ship it off to have repaired" clause and we could no longer take devices apart and repair them.
About a month before I left they signed an agreement to get those 1st generation glued together surface laptops. That verified my decision to leave.... No more repair, throw it all away.
Charging machine battery 24/7 cause this exploded batteries. No mechanic to turn off charging when battery 90 - 100%
@@GameBacardi Hi, with a properly designed OEM charger, leaving the charger connected 24/7 to the device should not cause any deterioration to the battery in terms of physical deformity.
They should have covered the tops of the output capacitors as well - they're very close to the un-insulated heat-sink too!
You should be thanked more often. So thank you!!
Thank you for thanking Clive .
"What a terrible design", you have the most entertaining way of putting things.
I like these forensic investigations. I refer to these entertaining videos as "Why things went bang" video series. They're like horror movies, because it's so real that some innocent, cheaply manufactured item might hurt, kill or burn your house down. And we just keep blindly accepting them as "normal" without doing anything as consumers to save ourselves.
I have a few of these power supplies, all of a smaller power capacity. I have taken some of them apart, and even when they look a little different on the outside, the components are the same layout as in this one. None of mine have ever burned, and the difference is in the smaller one that I have, the heat sink, and the inductor, are both small enough, that they can't touch each other. One thing I do notice is that on mine, there is a glob of that white "shmoo" on the inductor. I don't know if they were trying to keep it insulated from the heat sink, or if it was to keep it from vibrating. Either way, I am glad to know about this fault. I will keep an eye open for this in the future.
Darrick steele. The white "shmoo" compound is normally used to provide mechanical stability to components. As far as I'm aware the compound has no insulative properties.
I look after alot of desktop IT, and some of that is Surface Pros. We have had people loose PSU's so we got a load of "Replacement Surface Chargers" from a very well known IT reseller in the UK that sells to the trade. In no time at all staff were complaining they were feeling a buzzing when touching their MS Surface's. I tested one with my Fluke and sure enough i was seeing about 80v AC on the outer case !. So we issued an email to all staff to throw these chargers in the bin. Thus we got some genuine Microsoft ones.
That's common. It's capacitive coupling between winding layers and through the class Y RF suppression capacitor.
It's only about 100uA, but with 10Mohm input impedance, a meter will show a highish voltage. It's also enough to give a tingle from metal surfaces.
You'll find the same with most ungrounded power supplies including Apples.
component placement is one of the key design technique.
An interesting trail of evidence. Shame it took out the equipment it was connected to.
And probably no insurance coverage due to the fake supply.
that is what you get from cheaping out on expensive equipment !
The most honest comment I will ever put is that I watch RUclips a lot on my Xbox One, and which is an unsigned account the algorithm gives me _tonnes_ of content which I would want to or not want to watch, and lo one day I came across yours just watching you surgical commentary and the "Oh! Ok!" Surprised comment when you find out how bad, bad electronics are and the low quality cheap Chinese stuff too!
Brilliant content as always!
I don't know if it's practical after all the damage, but it might be an interesting video to reverse engineer that power supply and then show on the schematic what shorted to the inductor and why that made it go bang.
Already explained all that without a diagram, at least for those of us familiar with how switched mode power supplies are usually wired.
I just watched this video with an identical supply powering a Surface pro 4. Its the third supply I'm using, both an original microsoft one and another knockoff one have blown up with a loud smelly pop in the last 12 months (which I've put down to excess heat as these computers draw quite a lot of power). My better half also complained of constant electric shocks using this current one, though it didn't seem to put out more than a mA or two when measured against mains earth.
I'll tear mine apart now - if the inductor and heatsink are too close I'll modify mine and report back on here as another bad one.
Big thanks again, another awesome video Clive :-)
Hopefully just a few hundred microamps. 1 or 2mA would be quite painful up a single finger.
This is why I never buy aftermarket power supplies, much prefer a used OEM one to one of these aftermarket units for exactly this reason.
Of course there's no guaranty this wont happen, but seems much less likely something like that would be missed.
Seen far to many laptops with blown charge ic or worse totally dead fixing computers for years. Never buy this cheap Chinese crap. A power supply isnt something to mess with. Buy oem or high quality.
Thank you for the up. A relative too kept the cheap psu in a prebuilt medion pc, and fried his new at the time 1050 ti. being on tight budget, it was a deep burn. a expensive surface with a cheap psu is the cakes cherry. getting a good maybe gold psu will actually save you some quid in the long run considering those have better efficiency.
I think the chininglish is a good clue to the dangers inside.
I've seen this kind of failure result from very close lighting strikes which were strong enough to kill USB contollers in unconnected tablets.
I plugged in the extension brick which acts as the psu and adds more ports to my work laptop. It gave my monitor a warning of over voltage. Brand new from microsofts bussiness store.
The advantage of the brand name is that you get to send it back under warranty. Chinese junk, not so much. (Amazon might refund your money, but your fried equipment is your loss.)
The person who's computer blew up probably found skid marks too.
I really don't understand why these Chinese clone makes go through all of the effort of designing these things and then just get sloppy randomly with the actual manufacturing. I see this all the time with your teardowns. They're so close to making something perfectly serviceable and they just get so sloppy with the components.
Before I watched your channel I enjoyed taking things apart just to look at them. Now that I've been subscribed to your channel for a few years I take things apart just to see if I can make tiny modifications to make these devices much more secure without much effort. Thank you, as always.
The thing is it has never been just the Chinese, it is every company where accountants are allowed to interfere with what the designer specified, just to save a couple of pennies.
Rover Cars, just before their demise, used cheap components to cut the cost by a couple of pounds per vehicle. What were beautifully designed cars were subsequently plagued with problems. I imagine it made the designers cry. The warranty claims and damage to their reputation finally pushed them under.
@@chrishartley1210 sure, but a lot of these design choices don't even necessarily affect the cost, which is the most bizarre part
Its because the workers are complete lazy bastards even if making it better would cost nothing or doesn't take extra time. Pushing the inductor away from the heatsink would take 0.01 of second. They do the absolute bare minimum just so it works. No thought given to safety.
I don't think they know what they're doing really. They get some sort of decent successful design and then they copy it and they make mistakes on top of it. True expertise costs money. Maybe once in a blue moon they even hire a specialist to design a thing, and then over the course of time it... morphs due to manufacturing branch just implementing changes and them not being validated. There's a wild mix of things out there which some get reasonably close to getting it right, and those that are complete garbage and which cannot be helped.
That being said i think that's a phase. I think these companies go two ways, either they eventually die, or they eventually learn to do it properly and become a supplier for a number of tier 2 brands, with an occasional tier 1 brand in the mix, they go legit. The ones who have gone legit are then just not the subject of these sorts of teardowns, neither for the "cheapest on Ali" hauls, because obviously the stuff is anything but cheapest then nor the explosion post-mortems with funny spelling.
This is what surprise me too. Just like you say they go through the effort of making things but the end product is so shoddy. If they only put in slightly more effort they would be making top tier things. Something as simple as just the written English on the product. Then again, what isn't made in China these days? Even a good brand can fail.
Brilliant find! When I’m instructing my tech’s on my learned catastrophic failure troubleshooting techniques. I teach them first, that a comprehensive visual inspection is going to lead them to the issue 99.9% of the time.
Hopefully it took the stupid horrid tablet with it! (Enterprise IT guy who has to manage a fleet of these overpriced things here, if you can’t guess 😂😂)
In my industry we carry out physical qualification tests which includes vibration, specifically for issues like this. As the PSU was apparently CE marked, they should have done the same (but presumably that was fake). My suspicion is that whoever made the heatsink made it slightly oversize or the hole for fixing it to the FET was drilled in slightly the wrong place. For insulation (between the fouling part and the heatsink) they would have to use something like AshLam (essentially a thin, flexible piece of GRP similar to PCB material) as Kapton would eventually wear or creep through.
i find that even OEM chargers give zaps and blow up. Samsung, Apple, they all make this trash too. It's just people have a weird bias that the more expensive something is, the more of a HERO they are. What a clowny world.
You sure those weren't copies too? (I never encountered problems like these with genuine products, mostly user error or un-catastrophic failure)
I haven’t found that.
@@wisico640 nope, straight out of the OEM box straight out of the OEM shop. The charger that comes with the iPhone (the old ones when they had chargers), and right out of the unopened box of a scamsung laptop. Touch the metal by the keyboard and you feel a tingle. A good 60VAC to ground at 0.01A or something.
@@dimitar4y happenend to me once, with a dodgy ATX computer PSU, plugged in dodgy electric work / bad wired plug in a damp basement. What you experienced is in no way normal :/
@@wisico640 it's "normal" in the new world order. You will own nothing and you will be happy, and you will be productive, and you will be paying 60% taxes.
Thank you, that was a great diagnosis. I love it when you do this.
We had a similar experience with pinched wires, passed all tests, then after a while, the insulation gives way and creates a ground path. In our case, it just tripped circuit breakers.
Killed a Microsoft product? I'm already feeling better because of that!
Thanx for showing.
I also recognize a general design flaw in this unit.
They made the gaps in the PCB and seperation of the low and high voltage side useless by putting the heatsinks over the entire length.
Good PSU! Die micro$oft, die.
This is why I always go with an oem psu as it’s far less likely to be this way or at least take a cheap one apart to inspect it first if it is my only option.
"That's annoying! That's a terrible design!", said so beautifully!
The first thing I thought was like KiloSierraAlpha, that the inductor originally had adequate clearance from the heat sink but got dropped. Dropping it may have pushed the component into the heatsink and from there on it rubbed against the metal until it wore through the coating on the wire. There are multiple millions of economy products out there that perform satisfactorily every day. It's not because the item was a lot cheaper that it was cheap junk. If this company can build a power supply and sell it cheaply imagine how little it costs Microsoft to build theirs. Gouging is a huge problem with big companies. Thank God for the little guys who help keep prices reasonable.
This is why I don't trust cheap/generic power supplies. You need to use the original PSU for ANYTHING, not just what's expensive.
lots of brands that make good psu's that aren't OEM. It's like almost any other product you buy that might need replacement parts. OEM is almost a sure bet that it's quality, but that doesn't mean other companies don't make good stuff too.
You can buy cheap ass brake pads for you car that delaminate in month's, or good quality ones. You can also pay twice as much for oem parts from the dealer, but that doesn't mean they are any better than cheaper (but not cheap!) quality parts from another company.
The amount of times I’ve seen heatsinks bridge gaps of circuitboards is terrifying. Specifically name-brand-giant companies. It especially concerns me when the heatsinks on certain devices are naturally live and/or short by design.
Hi Big Clive,
You are a very talented forensic electrical engineer! Here in the United States I'm sure you would have been hired to determine the reason for an electrical fault or fire by our court system. Or maybe you already do forensic electrical work for Great Britain? Your testimony could determine the outcome of a trial!
Great videos!
Thank you for all you do!
can you open an old 90s laptop power supply? I remember they used to be the size and weight of a literal brick in the early 90s and steadily got smaller and lighter over the years, but particularly in the last 10 years to now where they're maybe only a fifth the size and less than a tenth of the weight.
Hi, if designed correctly it doesn't necessarily mean that a smaller lighter product is unsafe.
Good video. One can get tunnel-vision when trying to manage creepage, focusing just on the board, so air-clearance is neglected.
This is extremely useful to know and I thank you, especially because I have some young ones in my family and they've been watching this vid and are most grateful. Best regards -Wendi
often *WHY* inductors are usually heatshrinked in these types of switching power supplies.... and I don't think I've seen any conductive reaching across the isolation gap between the high and low power sides like that.
Hi Clive, the Heat-sink is connected to Bridge Negative to reduce the EMI produced by the Switching Mosfet capacitively coupled to the Heatsink(Ccase,Cinsulation) and preventing the Heatsink to act as an Antenna for that Switching Noise, It's common Practice to reduce EMI. But Clearly the Component Placing is bad.
Hi, the heatsink is not actually connected to Ground as in Earth or O volt.
If there's one thing I've learned in life, it's that you can cheap out on many things, but power supplies should never be one of them.
Trash bags and toilet paper top the list.
It was turned into a mini plasma cutter that cut a notch in the aluminum.
Besides, it even tells you will need to "Replace AC adapter" right on it. Who knew it would be immediately? 🤷♂️
Another example of why you never trust anything you care about to one of these no-name PSUs
*anything or anyone!
I get the impression that the inductor forms part of a buck regulator for the USB socket.
It never ceases to amaze me that people will spend hundreds of pounds on a phone or tablet, then buy a cheap and nasty power supply for it. As you've demonstrated many times, Clive, these supplies can destroy your equipment or even kill you. Please keep making these videos, Clive, people need to wake up to these death traps.
Hey Clive, what do you end up doing with all the old projects to tear down? That electrical waste must be a pain to dispose of
@@Okurka. Ouch, that hits hard! :p
Power supplies are simply not something I'm willing to gamble with for this exact reason. great video!
Nightmare scenario! It blew-out all their expensive equipment. The engineer probably never saw the physical product assembled after designing it on the computer, otherwise they would have been concerned with the proximity of that flimsy coil to that heatsink. When you're just looking at it on the computer all you see is "there is room between", and the sense of scale is different.
These "heat sinks" (in quote marks because having something like this in a completely closed plastic case with no ventilation is a bit pointless) are what came to my mind as the source of failure immediately. So many bad designed electronic devices out there it is scary...
It isn't pointless. How do you think any circuit in a closed plastic box radiates heat? The case gets hot.
1:00 that's not a mistake, it's telling users to get rid of that P.O.S charger
To answer your question @6:08 of "How many of these are out there...", A LOT. I work in IT, and Surface Pros account for about half the staffs mobile computers. Against our advice, some teams buy these cheap replacements when needed to try and save some money. In the end, they end up having to replace the whole device. Spend the ~$90 on the charger to save ~$1000 on a new device, don't try to save $70 on the charger.
I had a similar (cheap replacement) power-adapter for a MacBook once on my bench. They used a shielded cable for the low voltage side. After some use the cable shielding could sneak back into the casing due to bad stress relief of the cable and eventually made contact to the (live) heatsink. The owner of the MacBook got quite an electric shock from the (then live) metal casing of the MacBook. Luckily the owner and the MacBook survived that incidence.
I'll admit I still use "questionable" supplies from time to time. Supplies that look good, but you still have that nagging doubt. As a workaround, I usually earth the low voltage negative. Treat it as a Class 1 appliance on both sides of the transformer.
Hi Clive another great video, I feel sorry for the guy had his tablet and monitor blew up , regards mark
That looks like the power supply board I pulled out of my Playstation 4 about a year ago. It let out the magic smoke while I was about an hour into the game that convinced me to buy a PS4 in the first place. Fortunately, it didn't take anything else out and was an easy fix.