It's an LED lamp. Not just any old LED lamp, but our favorite type a dead LED lamp. And even better, it's a dead Poundland LED lamp and a ridiculously big one at that. I Actually traded my brand new working one with a local fisherman called Jiffy because he had this faulty one and I wanted to see the faulty one more and I wanted to see the working one.

So taking a look from the outside first as Jiffy spotted there is liquid in here. little droplets of liquid. Does that mean there's an electrolytic capacitor in here that has exploded? Or is it because liquid has got in and cause corrosion in some way through a lamp holder? This isn't uncommon for water to drip in through ceiling roses, but Jiffy said this was actually on a cable that was slung on a hook over to the ceiling. Rose so it's unlikely watch getting that way.

The filaments are eight of them and they're wired as two in series and they're kind of bridge together and and then the whole Latins are parallel fed top and bottom. but look of it. Okay radio. so let's get into the bottom of this and explore.

So I'm going to use the to try and remove the little rivet from the bottom if I can. This is a very big lamp. It's very unwieldy. I may have to use something sharp in the spudger for this.

it's kind of recessed Hold on I shall stick a pointy knife and at the risk of stabbing myself here. Oh almost. Oh, that is not easily coming out I may have to just basically start taking apart the wrong way. I'm going to break this blade am I I Would pause at this point, but you know what? there's no point because yeah, you can skip forward if you want to the point that you see it open right there.

Well, I'm not having any Joy of that at all. So I'm just going to get the side. Cutters I'm going to nibble here, being careful to support the the base and not hold the lamp just in case it bursts because that would be quite dramatic for one's hands. Oh crazy.

Uh, right. Maybe I'd be better using smaller Snips for this just to nibble in better. I shall try this pair of slightly bluntish ones. They're Tangled under stuff.

Let's even cause an avalanche. I did cause an avalanche. That's perfect. So these are bluntish.

These might be too blunt. Oh, there we go. There we go. So let's peel this away and see if we can get the circuit board out and see what's inside.

Nibble nibble nibble. For those seeing, why don't you use a pipe cutter to cut around this? Uh, I do think that would really work too well because uh, it's kind of an irregular surface and also, um, it is a kind of soft and the pipe cutter might just sort of basically roll around in that. My apologies if there's loads popping clicking noises that sometimes happens. I Microphone picks up the scrunching noises as I tear into things.

It's got a destruction Center right? We're getting better on here. I Think someone has suggested that, uh, something that has a problem might actually dissolve the lamp cement in here? I've never tried that. Maybe I should try that and just see what happens. It's always very hard getting it out.

Certainly, you can't use heat to get out because it is the same lamp cement that they used to use in the old days on the I Can smell this on the tungsten lamps and they used to get very, very hot so heat is not going to I mean it's designed to handle the heat. Uh, what if I go back to the bigger ships now. this is proving quite awesome as I say you can fast forward across this, but if you don't want to see the Carnage and it is actually quite significant Carnage Here, it's not coming off easily is it? It's got one of those little plastic housings under it designed to, uh, protect the electronics from short against the base, which is good. Very good.

Oh yeah, this has been making loud popping noises. My apologies for that. I can't really do much about that. It's just what it does.

Oh, this is rubber. This is rubber under here. I Wasn't expecting that if I'd known that I'd have just been doing this right. I can cut that wire now and pull off the rubber cap to reveal uh uh.

electric capacitor that is completely spewed out down here, right? Tell you what? Give me one moment I'll take this stuff out of this base and we'll take a closer look at it one moment, please. and resume. I Was hoping to fix this lamp, but that has been scuppered slightly by the fact that the uh do me or dumet tales that come through the pinch here are spot welded onto little wires that don't take soda very well and while trying to solder onto one uh, it's the spot weld came off where it attaches to the Dume metal. So the only way to actually fix this is to somehow get a connection up there or smash the glass and uh, then just use a central LED portion.

Maybe I'll do that, but anyway, I shall put this out the way and you can Marvel at the singed means of the circuit board. I'll just put this out the way. Loud Explosive. popping your glass in the background.

So major Carnage In this, the electrolytic capacitor has spewed its guts out. Then that's what the liquid was and the series resistor. The fusible resistor has done its job, noting that the heat shrink rounder is also just burnt up. There's a little metal oxideverage in this, which is quite interesting.

so take a look at the circuit board. Uh, this is the I'll Zoom down a bit. maybe not that much. This is a means incoming.

Supply Here it's got the live and neutral going here with the the series resistor and the metal. Ox I've wrist across that it goes through the bridge right far uh and goes through a diode and you know I'll just point out components. Then I'll show you the circuitry. Here is the 10 ohm sent resistor for the LED current.

Here is the 100 ohm Center resistor For the dimmer compatibility component. there is a linear current regulator, but on the other side there is another linear current regulator. I'm not sure the number because there's a big burn mark from the resistor. uh, the other on the other side that I said was for dimmer trickery or purified correction.

Trickery has a couple of resistors basically 10K 220k resistors in parallel. So 10K uh, there's this mystery component here I do not know what that is, it's in series The LEDs There's the capacitor that blew up and then a 560k resistor across that noting this not very good soda joint there. that is the connection to the LEDs and it doesn't look that great. It looks possibly as though that was arcing I wonder if this initiated a problem with that? Very strange.

Anyway, the schematic. that's where you want to see. It makes more sense. or does it make more sense? This one might not be far, everybody.

But anyway, let's go through it. The incoming supplier has that fusible resistor which is fused I'll make a guess 10 ohm. That seemed reasonable enough. There's a metal oxide diverged across it.

metal oxide Barista are also called a Vdr voltage dependent resistor is for clamping, spikes and transients. There's a bridge rectifier and then the circuitry splits into two sections. It has this resistor Network couple of resistors and then a linear current regulator and then it's got a diode over to the LED circuitry with its smoothing capacitor. I Think this is either for cheating perfect to make it look better than it is by causing current at the bottom of the same wave.

If you have a full wave rectified sine wave, the LEDs because you're quite a lot in series, only tend to draw current at the top of that. So two things can happen there. The perfect looks terrible because not current has not been drawn across. These areas are the same way, but also it can cause dimmers to drop out.

If the dimmers are the track type that require continued current flow, continuous current flow to latch, then the fact there's no current flow there can cause them to uh, jutter Jitter stutter and cut out and flicker or just not work at home. So what this does is that this effectively while the LEDs are off. this is on and it's limiting the current through a fairly low level and just acting as a resistive load across the supply. Then it goes through the diode through the LEDs The LEDs have a capacitor across them for smoothing.

This also makes me think it's for dimming because normally with these type of circuits, the capacitor will be over here, but it's over there. across the dimmers. it may be for dimmability. I'm not sure I Didn't check that there is this mysterious component I Haven't a clue what that is.

it's marked b2501 I Did not find anything similar. It's got a uh, the what looks like the facility for our resistor here to set some threshold. That resistor would have been basically there and going to that capacitor and it does look almost like a reference footage. I Don't know what that's for.

Um, in Rush Lemington's LEDs are not no? I Don't think so. It's very strange. Anyway, then you've got all the LEDs and then rather oddly, you've got two linear Regulators in parallel with just one common resistor and it's not like they're the same I think they're similar Regulators this one the uh, one of the eight pins is a dual regulator and it's an Sm2082eg. The one other side that has, uh, the skid mark right over the number I'm gonna guess it's an SM 2082d which is just a single regulator version.

a bigger package, but they've got them in parallel with a single resistor which is odd. normally I'd expect them to have each one of its own resistor, but they don't. There is also a little capacitor across those for clipping any sort of like sudden voltage change that could result in a current Spike through them. But here's the odd thing with the linear regulator for the Uh parafat correction or the dimming before the LEDs turn on current is flowing through the circuit and it's got a resistor that sets are fairly low-ish current about a tenth of what that is going through the LEDs and that has dissipated across these resistors.

but it's because it's then attached to the top of this resistor. As soon as current starts flowing through uh, the LEDs and The Regulators it will start flowing through this resistor and you'll see typically about 0.6 volts. I Think it is across that for the current sensing and that means that will raise up and then the current through this will be very low. So effective from the LEDs.

Come on. This virtually turns off. Um, so it really is just filling that Gap in the sine wave until the LEDs. Come on and that is it.

Quite a complex and weird circuit. I've never seen such a I've never seen three linear regulators on the one board before like that. Particularly to like this with a I'll zoom out a bit, particularly two Regulators like this that are basically in parallel with a single sense resistor. Very strange circuit.

was quite hard to reverse engineer because of that. The reason for the diode is there so is so this couldn't sort of ride the same way without being affected by the residual charge in that capacitance and that is it. So uh, thanks to Jeffer for uh, letting me exchange for that 40 land but was much more interesting than a fully working one and hopefully the other one will last longer. But uh, I would say that the burn mark in the circuit board around the lead from the um the LEDs almost suggest there's a bit of arcing going on here and that may have been what caused problems.

Yeah, Strange. I don't know what that Capone is. It's a mystery at it's just ralling me. You may detect that I Just I Tried so many search combinations I Could not find what that is.

It's a strange mystery component, but that's it. Uh, the mystery of the Poundland Exploding Capacitor go boom type lamp. I Don't really know what made the capacity boom. It's rated 400 volts.

It's a death beam capacitor. so seriously, they're supposed to be able to withstand stuff like this because their normal function is to destroy human's 5G desk beams. so they're usually quite rugged, but maybe it was just heat in the base that built up and caused that? Don't know, but interesting. Well worth reverse engineering.