It's another revisit to the little soldering iron well. Trilogy I Guess since this is the third video, I've looked at these units before. The first video I showed how to hack it to get a more controlled temperature range. The second video was showing how you could use the button on the front of the previous version to actually program the temperature by putting it into s calibration mode.

but when I did that I got a lot of messages saying they've released a new version. It's the B2 and it's you can't do that and it's a simpler inside. Well, this is a B2 version to the best of my knowledge and it took me a while to get it. I Finally found one in a little.

it was the last one the Shelf the box was open I checked everything was there and I wondered has it been returned as faulty? And yes, this button is not working on it so we'll have to fix it as well. So let's do a test first. When I clip this on because that button is jammed in, it just starts pairing up straight away. I Don't know if this is going to affect its operation now, but let's give this a test.

I'm going to light this heat up and then we'll see what temperature this is set at by default. So uh, that's assuming even works. Is it heating? It is heating? Okay, right now I'm going to pause till this has come up to temperature stabilized and then I'm going to use this uh, thermometer for soldi Irns to actually test it. Yes, it's 12 C in here at the moment that's quite cozy and warm for my standards.

Okay, Oh I can smell it heating up? Why? while it's heating up? I shall apply some soda onto the tip because you should always tin a fresh tip. Okie Dokie right? one moment please? I'm just going to pause and uh, wait for this to just uh, stabilize. It is now green which means it's come up to temperature. But let's give it some time to stabilize and then we'll do the test one moment and we're back.

And as always with these, it's running a very high temperature. Watch this. the tip is kind of discoloring and if I put this on here I'd normally sold at about 360 to 300, well, 350 to 360 C this is 480 Celius It's heading for that's way too high. Uh, I'm going to have to, uh, uncp this to the battery.

We're going to have to open this and explore it right? that is now red hot I Shall pause momentarily while that cools down one moment, please. the temperature has come down. Let's continue the video. by taking this apart, it's worth mentioning this base here has a soldier iron stand that Clips in and it's also got storage for bits.

It's quite nice. Oh and the little uh sponge thing, but they're not that great so let's um, take a look. I Get the feeling that the reason the button is sticking is possibly just a misalignment under the case. I Don't know if there's going to be anything really obvious we'll find once we've opened it up.

but to open up I'm probably going to have to remove that little Soder sponge base and the sticky label next to the button. That's no great deal. Oh, and this sticky button here, which probably it's probably warnings or something. it usually is.

This is my dangerously non-compliant modified Vde screwdriver, which is needed for getting into some narrow holes like this. A normal VD screwdriver won't go in, so the Health and Safety Executive loves to, uh, seiz those screwdrivers that have been modified like that as being hideously dangerous. and then you have to go and buy another one and cut it off again. That's because the safety industry is very detached from reality.

Let's see if we can pop this off. can certainly shave bits of the aluminum off. Is it going to come off? I'm not really too bothered by this. It's not something I'd really use anyway.

it's stuck on. but oh there there it goes. Oh was oh no, it was clipped in actually I'm talking crap. It could have come out very easily.

righty? Let's H just pretend that didn't didn't happen this. I could have heated it up and peeled it off I may do that. Hold on I've got my suitable heated pen here. hot air pen.

So generally speaking I'll just run over the label, the label. is not needed either, so it'll probably be left off for the time. I finish this. but I'll you know go through the formalities of removing it in a nice manner by heating it up right that do oh a bit off there.

Yeah, that was pointless as well. This is going so well. How about now? Oh, there is that sticky label at the back and it's off. Oh, that is a much smaller circuit board.

So here is the the button works fine. Now it's off. I think that was just misaligned. It's a little tactile button.

There's the circuit board. oh that is so tiny. it's unbelievable right? Uh, this unplugs but get the four connections to Soldier iron right to what? I'll take a picture of this I shall reverse engineer it. Then we'll explore it and we'll see how easy is this to hack.

One moment, please, reverse engineering is complete. Let's explore and we'll start by looking at the back. Not much to see I didn't take this connector off cuz it's got these very big blade connectors. I didn't want to melt the plastic or damage the circuit board because they're going into of Fairly large of ground planes and connect buses.

So I just left that on. All that's on the back is basically uh, these same ground planes and a few interconnecting tracks. The bit we're interested in and I'll Zoom down this. The bit we're interested in is this.

side that'll do actually good zoom. Uh, the connections. The soldier Iron we've got, the red is the positive, the yellow is the switch negative via this mosfet and we get black and white that is the RTD device, the resistance, temperature detector. And the good news is that it is hackable.

And even better news, you don't need to even open the base. You can literally do it all in the soldier iron itself as I'll show you later. There's an interesting chip here. Uh, it generates its own 5vt Supply it's got a regulator in it from the fuel supply voltage which is quite High Uh, it's like like, say, for instance, it's 5 cells, 4.2 volts, fuel charges over 20 volts.

Um, other things worthy of. there's the three connections brought on, the negative, the positive, and the uh, thermister and control pin. Um, and after that, we get a little connector for the interface board. Not really much more to say.

um I'll go cut straight to the schematic then cuz it is a very minimalist design. I shall zoom in just a tiny bit more. Let's see if I can do this. Disastrously bad.

No, that's good. I did actually manage to do a controlled Zoom There here is the mystery chip. Now the chip number is where is it? It looks like an M M29 A100 I typed that into Google Absolutely nothing came up at all. Google did not find anything like zero That's unusual.

So here are the battery connections. At this end, we've got the positive, the negative, and the Uh temperature sensor plus the Uh. the controller inside the battery pack can actually disconnect this therer if it to actually say I am flat, you know I've not got any charge left and it shuts the system down. The positive goes straight over to the heat elet I've drawn it as a zigzag here.

There's a diode across that, just presumably for inductive elements, just to protect against uh, the switch-off transients affecting the mosfet. There is a little capacitor across the mosfet for Extra Protection and there's a sent resistor down here of 01 ohm. which uh is to detect short circuits. If it detects a massive current through the soldier iron, it's detected via this 1K resistor to decouple it from the Uh input a little Uh filter capacitor and it will actually shut down if it detects an overload.

There's a little circuit board with the green, red, and Led and the Uh. Switch the push button and they're just got a common Zer volt and then it's just three outputs via resistors. the resistor in series. The button is just for protection of the inputs.

Again, it's quite a good design. The supply goes via this 4.7 Ohm resistor which I think is pretty much a fuse really and it goes down to coupling capacitor here and then it goes straight into the device and that is the device's positive Supply but it also generates its own 5vt Supply in here. um, the temperature sensing is. it looks a bit complicated, but it's okay.

It starts off the 5vt supply going via a 499 ohm resistor to the the Uh resistive temperature detector in the iron in the Uh Soldier iron bit and then it's got another 499 Ohm resistor. and the point of this is that this is permanently connected to 5 Vols which drops slightly when it's on standby. um, the current incidentally is 12 microamps in standby which is pretty good, but when it wants to actually read the temperature that when it's active, it uh pulls this pin here to the Zer volt rail to negative effectively and uh, then it's got a potential divider that it measures from a tap on that via this 10K resistor for input protection, a filter capacitor and then it goes to the input and that's how it measures the temperature. We're doing a little hack.

we're basically popping a little resistor in here in the soldier iron itself um, the thermister. When it wants to measure the thermister in the battery pack or see if it's to enable in the first place, it takes this pin here High that then forms a potential divider via this 10K the base value of 10K thermister which will vary up and down according to uh, the actual temperature and then it's got this decoupling resistor here from the input and this of filter capacitor here and again. When the Uh battery pack wants to indicate that it's low on charge and it doesn't want a load pulled, it can actually pretend that that's suddenly gone high temperature by disconnecting it and then the unit will actually see that voltage float up really high and it will actually shut off. There is a mystery thing here I Do not know what this is for when that goes High to actually activate that therm.

It also feeds this pin here via 180k resistor and a little decoupling capacitor. I Don't know if this is some internal voltage reference that's being activated I don't know or a comparator. Perhaps it might just be providing an input to a comparator. I Don't know cuz I can't find data on the chip.

It just seems this mystery resistor. the other thing it monitors that 4.7 ohm fusible resistor. Uh, it also monitors the voltage across the battery pack itself via a 2 meoh resistor and a 300K resistor. down.

here there's a filled capacitor and then it goes to the input so it can actually monitor the voltage if the voltage is too low. Um, it actually just flashes a code on the green LED But if the voltage was too low from the battery, it would actually know that because it would already be getting the signal from this. Not sure why they do that I Guess it's just maybe to check things are within tolerance. Um, that is it.

I've literally described everything that was much faster than the actual reverse engineering. Okay, here is the SOI iron and the module. Let's take a look at what I found inside I did rough a connection in the base unit from here coincidentally 52 Ohm resistance called 182 Ohms at its super duper perable hot setting. Uh, so by adding a resistance here, you can actually, uh, skew the way it reads it.

That's what I'm doing here. So I put a little uh, high value resistor in and then I've clamped my resistive substitution box across that now I have to say I think I screwed the readings up but just by having fairly long leads because uh, it, uh, it didn't quite turn out as expected. but I'll show you what happened there, but it gave a rough indication that um, 100 ohms uh gave a tip temperature of about 300 Cen once it had stabilized and 10 ohm 425. so I thought 33 ohm for the closest to what I'd normally use.

370 ohm uh would be ideal, but in reality I would suggest a 22 ohm and I'll show you how I put that in. We'll get this out the way: if you open up the iron while it's cold, you can just slip these bits off and unscrew this cover. Then you can slide this out pushing the circuit board at the back. I'll zoom out.

no I won't zoom out. I'll just keep it as it is and if you look at the Circle board, it's got four connections. It's got the two red connections which are the heat element and it's got the two blue connections coming out going down to the black and the white which are the uh temperature sensing bit. I added a resistor here see the resistor.

Let me Zoom down this and I shall focus on that I added the resistor with of heat shrink sleeving over it I put a 33 Ohm resistor and to be honest I'd recommend a 22 Ohm resistor or if you want a spicier iron, you could use a 10 Ohm resistor but all I did was take the white wire out cuz it was the longest. It gave the most room to move. put in the resistor. uh, put the sleeve over that wire, sorted it on and then slipped over and uh, heated up to shrink on.

That is the easiest hack now while we're here. If you pull this back, it shows that the actual iron the ceramic bit has these solder Connections in the side. That's quite odd I want they'll probably very high temperature? I'm guessing. not sure.

Um, when if you ever do expose those, make sure you put the sleeve right down and into the circuit board here because it has to go right down to, uh, allow it to go back into the housing to go back into the housing there is a little slot in here. Pull the cable at the back and it slides back in and you fumble around. Find that slot, it drops down. H This is where that would be sticking up too high if you hadn't sat it into the circuit board.

Set this back on again. Put your chosen tip on noting that they don't have the little uh sleeve that some of them have which is better provides better thermal coupling. Pop it back on and that is your modification made and your iron has been tamed down. Okay, let's Zoom back out again.

So that is it. It's the simplest I've seen. Look at the size of the circuit board. That is ridiculous.

It's so minimalist. They've really cut it down as always. It is set to this ridiculously high temperature to the point that it's going to really damage the bits. You can see the discoloration there would have if you overheat the iron bits.

It just causes them to corrode at the end very quickly. so it's better to tame them down. But that is it. And it's nice you don't have to open this bit because, uh, that turns out to be quite messy with all the labels and things coming off.

But there we have it. Uh, the little which version It's a B2 iron. It's uh, quite easy to hack you. Just basically you can open the IR and with another Soldier IR Keep in mind this is your traveling portable Soldier iron with the battery packs.

You'd probably have another iron at home I Have to mention that cuz people will say well, how am I supposed to Soldier it if I you know, can't use the iron Um, but uh, that. um now now I've completely forgot we saying yeah. So you uh, can do the hack inside here. um and without opening the base and that is a good thing because uh, opening the base doesn't involve ripping all those labels off.

But there we have it. Uh, it's a reasonable enough iron. It works very well, does the job. um, and as often with these little products, it's very affordable.

just needs that little hack to make it perfect.