Little Circuit Boards Dead Circuit boards. They're our favorite type. These are out of Twinkly lights. Let me Zoom down because they are very, very small.

but these are out of the twinkly Fon Now, Twinkly is a brand of addressable lights that can be pixel mapped with your phone and they're quite high profile. They have a big curtain of them locally um, in the sort of town cental area here and uh, they had a design flaw or a manufacturing flaw with their uh Ston lights where the original o-ring that the globe screws in against was 1.5 mm thick and the new one that they're sending out is 2 mm and that tiny little Gap that was left allowed water IND Its caused corrosion of many of the circuit boards. It's not a huge mega issue because they can supply replacement circuit boards and you literally pull what's left of the original one out. You can plug the new one in, but it's important to note that every single circuit board has an address effectively.

this is uh Light number two and they're all on a parallel bus, which is quite interesting because of the way they're addressed. So let's take a look at the circuit board in a larger format. The Cirer board looks like this cuz I've already taken a picture of one. it has the address there, number two and then I thought these were going to be addressable LEDs Um, cuz I' saw a brief glimpse of the circuit board before.

uh Kip Hake sent me them to take a look at Kip hes I thought these were going to be addressable LEDs but instead they're just standard 50/50 LEDs all W in series. It's a 24 volt Supply and they've got six LEDs so that adds up to round about 18ish volts. If we take a look at the other side of the circuit board, we have this very clever little chip. This is why it's got such a little pin out that I pin count that I Thought that those must be addressable LEDs All these are just designed for the decoding of the data that's being sent over the power lines and then this will just basically be a microcontroller with the power lines uh and then like the data receiving pins and then one serial output to the other side.

but it is not that this is a very clever little triip. So these xener diodes are effectively in series with the strings of LEDs I Thought there was some fancy reason for that, but it appears to be just to pack up the voltage of the LEDs to reduce power dissipation because this also regulates the current through the LEDs This chip is powered from the 24 volt rail via a xener diode, but also there's a resistor in parallel and then there's a little shunt resistor across that where you might almost normally expect to find a capacitor. After that, there are two um, in this case 8.2k resistors, but uh, 20K resistors in the older Pcbs and they go from the positive pin to the a couple of these pins. the output pins and I think they may actually be part of the Um the actual data reception, but it's very hard to say.

Let me show you the schematic for reference. The bits that had failed in these water log circuit boards were the resistors and there are only 1 2, 3 four resistors. So if you actually probe them and find the ones that failed, you should possibly be able to get your lights back up and working. So the Oing for a start.

the outside diameter. It's very hard measuring a squishy rubber ring without the proper tools, but it's round about 23 mm outside diameter. The old one was 1.5 mm thick, the new one is 2 mm thick just to make that tighter seal. The circuitry has all the LEDs I should have drawn sort of like little sort of like beams of like Me out shouldn't I But having said that, they're colored so you know they LEDs but it has the LEDs wired in series sets of six.

Then there's these xener diodes and I was wondering what they were for I Reckon they're just to pack the voltage up. get it as close to 24 volts within reason as possible because the red LEDs have the lowest forward voltage. so they've got the highest value zener the green of the next. uh, lowest for voltage.

So um, they have got a lower value xener and then of course the blue is the highest voltage. So uh, it's got the Uh 5.6 volts. you know it's a lower voltage one. and I think that's just purely because any voltage they can drop across the LEDs in the xener doesn't have to be dropped across the current regulator on the chip.

And that little Xeno there is going to take a bit of significant disapp away from this chip. Oddly, these two 88.2k or on the old ones 20K resistors are connected to these pins as well, so they must be doubling up as inputs and able maybe to measure the voltage in the 24 volt rail which I think dips but dips very fast and decisively to actually send the data. Um, there. It's interesting to note there is a position for a third resistor uh, going to the positive in the red input the power supply for the chip.

There's no decoupling capacitor, which is also very strange. But having said that, this might be down to the fact that they want to be able to reset all the chips very quickly perhaps or get a stable reset. and also they don't want any capacitance across the lines because that would mean they couldn't transmit the data across it. So there is a Xeno diode.

so 24 volts minus a 15 volts gives across this resistor gives about 9 volts to the chip when the voltage dips below the point that that be active I guess Uh Current can still flow through this resistor and actually provide power to the chip to keep it awake even when the actual the power lines dipping up and down. I Know some people have tried to reverse engineer the Twinkly protocol I Don't know if they've been successful yet, but it does appear that it sends an address for each particular Um pixel and then it gives the red, green, blue information, but it can looks as though it can address them randomly within it. It's not like a Serial string because it is just two lines going. the 24 volt line with the data and the common Zer volt line.

Uh, it also looks like this chip here probably is programmed with the Um with the address of the LED I Wonder if they do that during manufacturer? I Wonder if they just literally have a batch of Pcbs that are numbered two and they have that particular chip and a number batch Pcbs numbered 16 and they have that particular ship? Hard to say I Don't know if it's programmed in Citra There are some interesting Chinese LEDs with four pins that you can uh initially you can program and address into LED and then Bridge the pins together and just treat it as a two pin. LED and it is addressable, but they're kind of uh, odd. but anyway, that is it. So if you want to repair your twinkly, LEDs if your I mean the manufacturer has been very good in supplying Spear Pcbs and the O-rings but you have to tell them uh, which PCB numbers have failed.

But if you end up uh, out of warranty or whatever and you're trying to repair them, then these resistors. Check them. Um, you can see this is the PO common positive pin that is connected to all these resistors that are going to the the input pins, but then it's also to the xener and this one. So you can check continuity from that pin because these pins seem to be corroding as well because they're carrying the bulk of the Uh voltage differential and the current flowing across them with the water in it.

Uh, but uh, you can do a continuity check to these to see if they're okay and you can potentially the negative is just connected to two connections. Um, and ultimately these connect the LEDs on the other sides and the positive also connects the LEDs on the other sides. Um, The other thing to check once you've tested those are all valid or Bridge them if they're not, check the value of the resistor. If the resistor has gone open circuit as many of these ones had where they've been uh, soaked in water, then you can basically just desolder them and put a new resistor in I Suppose Really? given the amount of room.

No, that's kind of on the back so there's not a lot of room. It would have to be a surface mount resistor, but um, these resistors seem to been the prime culprits. All the Xeno Diads were fine. The chip looked fine.

it was just the resistors and the sort of connector pins that had filled. So that's how you could, potentially, uh, repair your twinkly lights. Good stuff. Uh, They're quite an interesting product, But there we have it.

Um, it's fixable and it's quite unexpected and interesting. circuitry.