It is a pre-exploded device and pre-opened. It has been explored, it's very inside and here's the story so chris sent this and he said as a power supply for a microsoft surface that blew up quite spectacularly moments after being attached to the computer. It destroyed the surface. Beyond repair and the external monitor attached to it, excellent we like to do a good job here.

So let's uh get this out. What voltage is anyway? It puts out 15 volts at 2.58 amps and 5 volts at 1.5 amp. It's got the usb port for the 5 volts and it's got the cable coming out here, which will cut off, don't need that it's just going to stop it being easy to open right here. That is possible.

A lot of the current went down that cable, because that's what blew up the the tablet and the monitor. So now, let's get this out of here. It's also worth mentioning uh. It's called replace, ac adapter, not replacement.

It's all done in chinglish, um model number dhm, 1800 input 100 to 240 volts um warning. It is normal that has certain temperature increasing during use. It's all it's it's a cheap clone right. Let's get down close to this and knock one out.

What do we see? This is a been explored um. One of the problems when they blow up is because it's just a mess. You can see. Tracks have been vaporized here, but you don't know what initiated the problem, because sometimes the fault itself obliterates that problem.

One of the things that comes to mind if a fault occurred in this side, if say, for instance, it just decided to go bang as they sometimes do, there's a possibility. There was flashover from this side, and i do see at the opto isolator, where it's going from the high voltage side to the low voltage side and these pins here in that isolation, slot do suggest an opt isolator under there. That suggests that it could have actually flashed over onto those pins um. Oh sticky, shmoo.

Oh, this gets heatsink compound going on to the plastic case, um anything obvious here. The tracks around the transistor are intact. I would have expected them if that had gone. I would expect them to blow first, but this has been something significant here, but having said that, uh, when a fault occurs like this and the attract vaporizes, even if it's a small one, it creates a metal plasma, a metal loaded, conductive plasma.

That then causes basically a sort of like an arc lamp. It just initiates continuous current flow through that and it engulfs, and that's what makes it go bang with a really big flash. What other routes could have gone? It could have gone via the transformer. The transformer is a common failure mode, let's tilt this back, can i tilt it back, not really um.

There's the output diode another possibility here. Oh that's a plastic case. Diode though another possibility is that you know these metal. Heatsink fins can actually come in contact with something else.

It almost looks like there's a bit of splatter there, but i don't see any skid mark. There is a little bit of skidmark on the bottom here, but i don't think it's near any of the the low voltage components the transistor in here is also plastic. So, oh i'd, look at the way the heat sink comes down to low voltage, but is it clear? Oh look at this. Look at this: let's, let's zoom down in that, in fact i'll bring it up to here and we'll focus on it and uh.

We can actually zoom in a bit further at that. Do you see what i see here? It's actually a little skid mark right next to the inductor, but that transistor is plastic. Is there anything else connected to this um hold on i'll zoom out again and i'll? Go back down to here, which is the best place to be for working. Oh there's a little metal tab.

Just in here, can you see that the little metal tab just uh, anchoring this heatsink down? Oh and it's connected to this track, which is possibly this track that initiated this failure. What would that have been that is going over to there? That is probably class y capacitor over there? So this is probably the negative connection to the power supply. So this little inductor here, let's bend it over and see if it's actually all city, let's just get this thing out completely and see if we can actually see uh, is this going to really help things much yeah? If you look very close at that i'll bring it back up again i'll bring it up to about here, focus on it. Zoom down and you'll see the little telltale splatter of copper there, where it's rubbed through on that aluminum heatsink, and that's where the fault current is taken to the circuitry.

That's annoying what a terrible design they must have known. Something like that could happen unless it was designed for a different inductor. How many of these are out there, because that pretty much means if this was touching when the surface was plugged in or anything was plugged into this usb port? It potentially became live at mains voltage and what connection is that that is going over to the usb um and when that became live? It means voltage. Let's see, where's the tracks for this when it became live at mains voltage.

If you were holding the tablet at a time, you might have noticed a stronger tingle than normal from a charging tablet, because, technically speaking, if this was touching, the tablet would have been live. But when it was plugged into the video monitor, then that provided the path to ground and that's why it's blown up the video monitor as well, because the rectified current has flown through this metro, heatsink onto that inductor and then along. It must have found its way along the low voltage signal, the 15 volts of line to the tablet and then found that, because the tablet's not grounded if it would have just been live on its own, but because it was plugged into the monitor. The current has continued along the signal wires, which is blowing up all the circuitry in the process, and then it's gone to ground via the monitor and that's just killed the monitor as well.

How annoying what a terrible thing! One oversight, if this is because they needed a big heat, sink to try in a plastic enclosure to try and dissipate the heat from this transistor behind here. Can i get that off, i kind of want it off. I want to see a bit more. Let's see if i can unscrew that screw, i can unscrew that screw, but it's not going to help me get the oh there.

It is. Oh, it has. Oh, it's left it's taking quite a divot out of that. That would bring quite a flash, not as much of a flash has happened another bit so i'm guessing the transformer has been absolutely fine.

It's just that pure placement of the components with the low voltage side being next to the high voltage side. And again it's only that case that heatsink could not. You know it could have just been put onto an isolated pad here, but they've actually connected that heatsink onto what appears to be the ground for. What's left of that, circuitry odd, i'm just uh, i'm just pondering things here.

Here's the capacitor this capacitor yet is the negative it's the negative of that big fat capacitor there that's uh connected to that, so that is uh. What initiated the fault that bridge on the from the input side to the output side. That has then caused this to actually blow up, but also in the process. It's the past enough current to actually blow up the equipment.

It was connected to what a shame. It shows that you know sometimes you're better actually getting uh. I mean it looks a relatively good design, but they've just it's got flaws that would have been picked up in high voltage testing. Perhaps, unless it's vibration during transit, maybe they did test it and the vibration that, by rubbing against the aluminum during the transit, is basically just worn away through it.

The fix here might be if they wanted. A quick fix would be to just stick a little piece of insulating material down onto that inductor, which is a filter component to actually block it from making contact with that aluminium. That would have been the cheapest fix, or just take a section of that aluminum out. So the inductor is nowhere near it yeah just this is what happens sometimes, when you design things that you don't really consider odd things that could happen you, maybe they just were thinking in their head.

You know it's grounded, so it's absolutely fine. It's connected to the mains negative and they just didn't really consider the vicinity of those components just perhaps because they were clear on the circuit board and they didn't really think of the aluminium aspect. But that was interesting. It was well worth taking apart.

It's just one of many uh situations where a tree power supply has caused issues and blown something up, but it's also worth mentioning that some prominent high quality branded equipment has also been caught out with the same sort of things where the person designed the aluminium fins. Maybe they increased the size just because there was a issue with overheating and they just filled all the space, but they didn't think about the component that was actually going to be in the circuit board. So it happens to good companies as well as uh as cheapy companies, but there we go interesting well worth exploring.