Hi. In the previous video, we took a look at this casio. FX 260 Solar 2 Calculator did a review and teardown of that I'll link that in if you haven't seen it, but we saw that a it had a spare pad in there with potentially a spare reservoir capacitor because this is only solar powered and it does operate for a little bit, but eventually it will actually die on you. so it does a reasonable job.

But I thought maybe we can actually hack it, add in some extra reservoir capacitance and see if we can actually get that working a bit better. Potentially maybe probe some signals around. Let's take a look at it. And by the way, for those who, people who suggested that this pattern in here was like a carbon fiber and this front panel might actually be carbon fiber I Don't think it is.

It's just designed to look like that I think it's just you know, like a like embossed kind of plastic or whatever you call it, giving it that qubit type a carbon fiber look. But I doubt it's carbon fiber on a nine dollar retail pocket count. So here's inside. There's not much to it.

There's a blob as a couple of passives around here, there's a solar cell and there's the LCD So what we're interested in are these passives here and you might be able to see that there's an unpopulated capacitor there and it looks to be in parallel with this one next to it and that looks like it's probably the reservoir capacitor for the power rail coming from the solar cells. that so the charge on that determines how much how long it's going to last when you remove light from the solar cell. Now one thing I was curious to try: I've got this tritium nuclear battery here which I got from my nerd rage who you are sent this to me have to link in his video at the end of this I've always been meaning to do something with this and I will eventually. so I thought I'd tried it's got these I choose with tritium in them and they glow in the dark.

It's almost pitch black here in the lab and my camera's gained up and you can see all the noise and crap. I Just wanted to see if this was enough to actually power the unit and well, unfortunately on on it ain't so we're not gonna get a nuclear-powered battery anytime soon now. I believe this one which he made and sent to me. it did actually fully characterize this and you'll have to watch his video to get the performance graphs.

The peak power out of this was I think one point two microwatts. so obviously yeah, that's not good enough Oh Bummer. Anyway, what we were interested in is that little capacitor down there and you can see that the C 107 there is in parallel. You can see the tracers going across so like a buggers off in there and of course it's going to this like ground what looks like a ground over here.

but we need to measure that and then it goes into these three caps here. and no, they they're probably charged pump caps because they go in and out of the chip like that. These ones are three going to ground. So maybe there's some decoupling for the LCD driver for the divider or something like that, perhaps.

But anyway, I think my theory is right. this is the reservoir cap and we should be able to add another one in parallel. like I'll try and find the biggest like at what is that? no 8:05 ceramic the biggest or even you know Jam a 1206 on there or something. see if I can find like a why do they go these daisies? newfangled ceramics like 100 Michael something probably.

So let's just buzz this out. Let's go from the negative over here. and it doesn't. It doesn't go all the way through, you can see it.

sort of like sneaking around there. And anyway, let's just buzz it out. see if that actually goes to the needy side here. And yep, confirmed.

Oh gosh, our probes there we go, no workers, so that's ground next. Let's see if yeah, oh, that's going in there as well. Let's see if this goes to the positive side. No, it doesn't.

Okay, so there's something else in the way of that solar cell that's interesting. So although that doesn't connect directly across the solar cell, still makes sense that that is the reservoir cap. In fact, what we can do is actually suck that out and see if it still works. But let's and before we get medieval on its arse and start heating the bastard off, let's just probe some signals.

So flip the solar cell, all the electrons going to fall out. Let's just measure how our battery over from battery. Now Solar Cell Voltage. There you go.

Two Point Seven Five. That's all right. No workers. and let's go on the other side of this cap here.

See what we get? Whoa. Two Point Eight Six I may have moved that. So Two Point Eight Six. Let's not move anything I Know There we go.

Yep, so it's exactly the same voltage on there. So that's pretty much I confirmed that that is the reservoir cap. As you'd expect, it's the biggest cap on there. It's connected through the ground.

It's it's got to be the reservoir cap. But because it doesn't actually connect directly through to there, then Oh Twenty Four Ohms, there you go. There's probably some like internal Sarah Let's put it the other way. Ah yeah.

Well, no, that's there You go. There's some sort of switch in there. There's probably some MOSFET switch or something in there doing that. Okay, I sucked it out.

Let's measure that baby. How about what do we got? Yeah, a couple of. Mike Sixteen Point Eight Mike Yep, that's a reservoir cap. If there ever was one.

Wow Let's see what? God Well, let's see if it works without it first. So what does it should And it does, but cover it up shouldn't last very long. Yep, there you go. So for those playing along at home, you can actually calculate probably what value cap like how much longer it's going to last if that's sixteen point eight micro farad's and it starts fading pretty much straightaway are maybe I don't know, you could kind of ballpark that how much better.

Anyway, I'll see what value caps I've got I'll work to all them in there how much height we got but I think we've got a one in the back of our KCI look at all their nice ridges in there that's holding in. You can see the marks on there holding in the solar cell that pad there's holding the LCD in place. Very nice. They've got all the struts in there for rigidity, whatever you want to call the damn things and we should have no, yeah, we should have no shortage of room in there.

it should be in that void in there. Actually, she'll be right. This will do the business. Passive components for energy harvesting.

It's exactly what we want. AVX I Kindly set these into the mailbag. you may remember some time back voltage is never going to be an issue. in this case.

One my 10 Mike 2.2 Mike 47 Mike they're A there are 1206 yeah those that we can still put those on and now they drop back. yet they go up in voltage I think I know Oh man, we got some super caps in there. Look at that now. of course if we had the room in there, you could put like a small tantalum or something like that there to be then I'm gonna fit on the pad or you could bottom in.

but you know? Yeah, but this could be more interesting. Look at this. the mobile sample kit not only got 10 of them, but we've got Niobium Oxide. Niobium that's near enough oxide solid electrolytic caps.

Check out this bad boy as size S Pakis. It's like it's sort of like equivalent of an O 603 type size 100 Mike at six point three volts now we're talking CSR isn't going to matter. but yeah, these are designed for like mobile phones and stuff like that. but 100 Mike Again, no workers.

tiny little talams and tantalum or ceramic in this particular case isn't going to matter. But oh wow. 220 at 4 volts Now we got oh oh it's tempting to put those bad boys on there. We can get 440 Mike's on there.

Oh I think we're talking now. Yeah, more capacitance. Now here's an example where case size matters. They're both to 20 micro farad right? But look at the ESR 3 milliohms or three Ohms or a hundred and fifty millions for these ones and they're both.

It's not much in the voltage, you know? Yeah, these are going to be smaller because of the smaller voltage, but look at the size difference. These are d size ten lamps as opposed to these cute little s size with jobbies down there and they're both the same capacitance. Look at that. but that's what the larger size gets you.

Not only can it get you higher voltage, it's it's a trade-off but also gets you much lower ESR as well. But in this particular application ESR doesn't matter a rat's scrotum. This thing should last forever. But the trade-off is is that it could actually like change the startup because that cap will take time to start up so you can't put like an infinite amount of capacitance in there with low ESR because it'll just suck all the energy from the solar cell effectively shorted out and it'll take too long to power on.

So the it's got to be a trade-off in there. This may not start up straightaway and that is what a soldering iron burn looks like. Just don't ask. All right I Only sold of one on the X It didn't quite fit, it was just easier to our angle one across.

So let's have a look. It works Okay, let's see how long it works for here we go: 69 Factorial: That's giving it us a heck of a workout. the poor little processor. she's still going and going.

It's like the Energizer Bunny She then became the Jerusalem Unnie in a stroke of reverse marketing. Um, yeah, it's it's doing much better than what we what we had before. It's kicking some serious butt. Here we go.

It's starting to fade now up. Yep, still. Yeah, it's gone. Basically lasted about two minutes, but that's a decent upgrade.

And this is interesting. If I actually put this on current and short out the solar cell. We basically dink up. Not it.

it wasn't doing it before. Anyway, let's switch it back. Notice the LCDs Actually, it's coming back there because we've got some charge building back up on that cap after we shorted that puppy out. So please excuse the beep in.

let's short the cap out directly. Shall we? There you go, Can short it out directly and that that sucker still works. That's interesting. I Found an interesting mode on the Eevblog leader too.

If you actually apply some, do something on there and get some current flowing. It actually it overrides the insertion alarm. The probe insertion alarm. Interesting, but basically shorting out that cap doesn't stop the process of working.

That's fascinating. Okay, so let's try this. Flip the solar cell up where point two volts. That's obviously not going to be enough to operate it.

See how quickly it turns on ready? See, there you go? They should. Probably it takes a second or two. What was that? Maybe two seconds to turn on? I Don't know. So yeah, he could argue that 220 microfarads might be a bit too much.

The trade-off there is: you know you've got to wait longer for it to power on, and that's going to be more annoying than any benefit you get from the solar cell. But really, if you're operating this thing as you saw in a previous video, operates under 20 Lux of light. anyway. so you know we're just doing this for shits and giggles, really.

And for those who want to know what current we're talking about, 50 micro amp range. here, it's charging up the cap. of course. There we go.

Don't worry about the negative. Oh yeah, there you go. 35 micro amps? something like that. No workers.

No wonder we couldn't power it from that nuclear battery. All right, it's scopa dope time. Let's have a look e here. and we've got five capacitors here.

I'm going to probe the bottom one here and we expect this to be a charge pump. Tada 150 Hertz You can see that in the bottom left corner there. that's the next one up. lower amplitude as well.

We're on 500 millivolts per division, by the way. so that's you know that's the 2.5 that's full scale. That's half scale. Next one up, nothing.

It's got a bit of Ripley on there, and yeah, bit of ripple on it. So yet they're probably bypassed for the LCD ladder. and that one's all right at the top, right at the top. One volt per division.

Here we go. So that's the height up here we go at one, two, three and a half fault. So there you go. they've got.

ignore the man behind the curtain there. And for those who are curious to see the LCD drive levels, well, here's one of the segments over here. There you go. Operating at thirty one point, three, five, Hertz And if we get one of the multiplex pins, let's try and get lucky.

Punk. There we go as a multiplex pin. The reason that was around is because of our trigger level I think was right on there. There you go.

there's our multi level our DC by our multi level bias for our multiplexed LCD So another one there. There you go. Neat. three levels, standard multiplex two LCD Driving For those who are wondering no I can't find any sort of like you know, pin, strap, jumper, or anything like that to enable the NF model, the No fraction which doesn't which has the button there, but it actually doesn't have anything printed on it so I can't actually I'd see anything unless anyone can see anything else.

and you know they're pointed out to me how to look around and I can't see anything. So maybe there's some sort of programming that goes on through the pins or something at the factory? Perhaps I don't know, but there doesn't seem to be any obvious jumper or pin strap to hack the NF model into the standard model. So I hope you enjoyed that little. I follow up on the FX 260 so were they're just adding some capacity.

Um, so that the thing doesn't turn off beautiful? Well, it can last for two minutes. There's not much penalty in terms of the turn time there, but if it bugs me, I might lower it to like a hundred Mike or something like that. but that's a reasonable upgrade you're gonna want to do to your own calc anyway. So if you liked it, please give it a big thumbs up.

As always, discuss down below: catch you next time. But wait, there's a bonus. We're going to do a quick teardown of the casio FX 9, 9, 1 ax which is basically their type. the class class whiz that's basically their top of the line are non programmable scientific calculator does graphing, spreadsheets in the whole like I've done actually a video in an original mailbag from a long time back, but I've actually split that out pulled over on my Eevblog to channel so I linked that in at the end of the video here.

Anyway, let's open this thing and by the way, this is fantastic value. The 260 is only like nine bucks us this is under 20 bucks, so like basically double the price for like 10 times the capability. Absolutely phenomenal. So do yourself a favor and pick one up tomorrow.

There you go. we're in O8 Roni haven't seen a trainee before. It sounds dodgy doesn't it? anyway? Um, that's interesting. They've got metal on the back of there that's not for are shielding purposes.

That's for that'd be like a stiffening backplate I would be guessing for that LCD module. Anyway, that's going to have chip on board because we got a tape bonding attachment here. It's just a hot hot tape bond on there and so they're going to have a chip on board chip on tape driver up there cuz clearly there's not enough segments to drive all that. so that's going to be in fact.

that could be like a PCB in its own right. Really. So anyway, as our storage cup done a little cut out there, no workers and it's not much else is there. Once again, it's just the black blob and that's pretty much all she wrote.

But once again, um yeah. fiberglass PCB in there, no workers and that's and you can see actually see the membrane under there like that. But yeah, I won't take that off. but does the LCD pop-out hang on? Actually that it looks like the glass is embedded the the aluminium back in plate? Yeah yeah, that's that's that's factory-fitted that's the backplate for the LCD It comes like that.

Um yeah for our stiffening purposes and probably adds a little bit of heft to it as well. which is, you know, probably what you want. so they might have actually they might have specified that. Hey, you know, we've got this reasonably big calculator you know, don't want to slide around on the desk and I probably should have used rubber baby buggy bumpers on the bottom instead of these little plastic nipples.

Nothing worse than a plastic nipple. Cheese is no fun in that at all. And they went oil it said, maybe add some. They specified, let's add some heft or something like that, but it could have been, you know, who knows.

but that's just a guess. Anyway, there you go that's inside the FX 99 1x catch. next time.