EEVblog

[@mikeselectricstuff]

Top tip for peeling off films without tearing - roll it round a cylindrical object ( pen etc.), so pull is even across the width, avoiding stress points that initiate a tear

[@profpylons]

mikeselectricstuff How about putting the chip in your x-ray machine?

[@LazerLord10]

I couldn't stop seeing that main chip as just a 2D printout of a photo of a normal chip.

[@EEVblog]

Yeah, looked totally weird.

[@jonathancook4022]

It would be considered remarkable even today, But back in 1983, people must have assumed that Casio employed witches!

[@johnfrancisdoe1563]

No One In Particular At 1983 tech, that's actual chip layers. Dave probably scraped off part of the uppermost metal layer of the chip.

[@RemcoStoutjesdijk]

This IS a normal chip. Casio have shaved it down just right down to the lead frame.

[@Knight_Astolfo]

yeah, it's really messing with me Dx xD

[@henninghoefer]

Things I found interesting, that you didn't mention: • at 5:53 you can see that the top film is also the polarizer for the LCD • around 17:46 there is the (old) NEC logo on the back of the board

[@richardincam]

I am really looking forward to the reassembly video

[@bhoot1702]

Aah haa

[@MichaelKathke]

I remember a visit to the Hannover Messe (Germany) with my dad, where CASIO showed all the layers of the SL-800 in a showcase. Back then it looks like SciFi to me. I was very impressed!

[@gertnutterts988]

I also can't help feeling sorry for that calculator. It lived a faithful life, always willing to calculate, for about 35 years... until it met a certain Aussie. At-least you made it's autopsy worth it, honestly worth seeing it. :) But lets just hope we can forget you cut it open while still functioning. Maybe next time, cover the solar-cell. Like using a blindfold. ;)

[@johnfrancisdoe1563]

Gert Nutterts Vivisection, not autopsy. Test subject was alive during the procedure.

[@AureliusR]

Dave doesn't give a toss. He's just completely out of touch with his original audience. The KZbin algorithm is all he cares about.

[@KG5IF]

Me too, felt bad for the old calc... Wonder how many more years it would have remained operational.

[@MsMarciax]

Just one of them moments when you feel like crying but find you are overcome with utter excitement all at the same time. Utterly awesome :)

[@EEVblog]

Indeed

[@KRAFTWERK2K6]

i don't get why these are not produced anymore today. As a kid i had a "creditcard" sized solar calculator but it was a bit thicker. Still thin enough though and it came with a nice metal back to keep it stable and also had a name-stripe where you could write your name on it. Sadly the ones you get nowdays are all plastic and feel very very cheap and i would not trust them to survive everyday carrying in your wallet. This Casio Model would sell like crazy today and would be great as practical giveaway. These things still feel super futuristic.

[@pdrg]

"I had to find out" - the curse of the engineer!

[@jonathanfadden9299]

The buttons may not be dome "clickers" but resistive pads that sit on the conductor fingers. Changes in resistance will occur with pressure is applied to the carbon. Dave, great video! Thanks.

[@what-uc]

Of course, like Edison's carbon microphone

[@fabimre]

I can't keep on watching you murdering this poor and unique calculator. It's like you slaughtering the last living Dodo!

[@DanHaiduc]

Entropy gets us all anyway. My old high school chemistry professor had a saying: "Smile. Tomorrow it will be worse." No point fighting it; instead, make use of and enjoy what time you have on this world!

[@sheadjohn]

do you remember clear calculators that could sit ontop of a overhead projector?

[@Sparks68]

They're still being made - but my question would be who's buying them as the overhead projector is a long dead and buried conference room device - replaced by digital projectors years ago.

[@Darkmaster5629]

​@@Sparks68well... visit any German school. You'll find at least one.

[@raleighsexton7734]

Bought one in 1982. Dark blue with pink stripes. A couple of judiciously placed pinholes to assure contact in certain places on the keyboard were the only giveaways to construction. Carried it in my business card case for two decades before it finally wore out from daily use! Couldn't throw it away even then, still in a drawer somewhere. Cheap and good! Great job, Casio!!!

[@AgnostosGnostos]

At 00:54 he say that it is a four function calculator. It has obviously square root function and memory. It is a part of calculator war between Sharp and Casio during 70's and early 80's for the thinnest calculator. At the end Casio won. Check a video about this war in KZbin with the name: Japanology Calculator.

[@reggiebenes2916]

Damn, these things working go for well over 100 bucks. That teardown was great. I can't imagine it would be possible to make anything thinner even today.

[@EDGARDOUX1701]

While tearing down I felt like my life was going away :(

[@luloian]

dave, my mind ins going away.....dave stop doing that. daaaave.... lets sing a song.... daaasy daaasy give me an answer too.. im half crazy.......

[@EDGARDOUX1701]

LOL !!!!!!!

[@Bodragon]

"...give me an answer, do" , not "...too"

[@AttilaAsztalos]

Stopped watching as soon as I heard "teardown". No. Just, no.

[@GRBtutorials]

Dave is the only person in the world mad enough to tear it down!

[@gamingwithkendirk8181]

At 24:55 under the memory array you can see NE what might also be C

[@thejavaman53]

Gaming With Kendirk but looks more like R or P

[@movax20h]

Indeed it looks to be NEC. Manufactured or designed by NEC.

[@zero3609]

Great teardown of an awesomely engineered price of hardware many took for granted. Thumbs up

[@danweecc]

The square-root would make it a 5-banger I suppose, or a 6-banger if you count the percentage function.

[@qwertykeyboard5901]

dont forget the extra functions under */- like 6*= is 1/6

[@JMacQ77]

Really amazing technology and engineering for one quarter of a century ago. Also, very impressive teardown skills, Dave. You have the steady hands of a neurosurgeon!

[@zeproo]

1983 guys. These engineers were probably ancient aliens, how could they ever produce that.

[@EEVblog]

Yep, I'll go with ancient alien tech.

[@gustavrsh]

This is incredible even for today's standards

[@AstralS7orm]

Come on, nowadays you can have a calculator, smartcard running Javacard with a cryptographic engine, 4 banger buttons, RF receiver, display, all in a credit card. With some flash to spare for applications. Just look up OTP cards. Granted, I haven't yet seen one with a solar panel and more buttons together, but it's definitely not out of question. (Internally, most of them are 8-bit AVRs...)

[@joshuarosen6242]

AstralStorm Whoosh. That's the sound of the joke going waaay over your head.

[@GodzillaGoesGaga]

I have to admit Japanese engineering is incredible when it comes to micro machines and small scale stuff. The whole bond-out to leadframe and SMT technology that they did in the early 80’s is still spectacular.

[@jasonbrindamour903]

Thanks for tearing that down Dave, I know you didn't want to, but that was pretty damn neat!

[@willyrivero470]

I agree with you. Casio used to build some of the most incredible, best looking, best designs and very reliable calculators ever built. I became nuts for calculators as a young boy because of CASIO. THANKS! Great video.

[@MartinEKoch]

Impressive for 1983! Thank you for taking apart and sharing!

[@spidereyes6290]

Hi Dave, have you heard of Robert Baruch? He is doing some brilliant work removing dies from chips, archiving high res digital photos of them and then reverse engineering the circuitry. It's very impressive. Seeing that die circuitry just reminded me of it. Worth a look for anyone into that sort of thing :-)

[@todesgeber]

the calculator may be rare, but the teardown is one of a kind!! thanks Dave!

[@dwagner6]

Just truly love all of your videos and banter. I have zero electronics background, but I’m already planning a basic lab to dive in and repair and attempt some simple projects. Thank you for all of the crazy informative interviews.

[@Draugo]

Every time I see a chip under magnification I'm amazed that we can both create that level of detail and see it magnified to viewable level.

[@michaelhawthorne8696]

Casio are the best at calculators, I loved their VFD ones, they were so vivid in any ambient light, and seemed to do every calculation, even fractions and Degrees Minute and Second conversion.

[@richfiles]

The µWatch and the µCalc were THE original projects that brought me here. I never even knew about the KZbin channel, only the forum. I discovered the KZbin channel independently of the forum in 2012 when KZbin recommended your teardown of the world's most expensive hard drive (#395). I'd LOVE to see the µWatch and µCalc resurrected. Wish I could get the boards, the chips, the bits, and throw them together!

[@njphilwt]

Very cool. Sometime around 1981, I bought a Casio calculator watch that had small tactile aluminum buttons and full scientific capabilities. It had everything including x^y, trig functions - you name it. The extra functions were accessed through shift combinations, and there were so many built into the chip that I kept finding hidden ones. I’m pretty sure it’s still around here, somewhere. Now I’m motivated to find it...

[@grumich4084]

NJ, I have one that sounds similar to a small, folding calc I bought in the early 80's. The thing did EVERYTHING and folded it was about two credit cards thick and (I believe) smaller in footprint than a CC. I still have it ... "somewhere." I gotta dig it out now ... :)

[@AdamTheAd-vanc3d]

Grumich I remember them. There was a black plastic type . A gold and, a silver one . Lovely watches , think i may have to treat myself to one again.

[@AdamTheAd-vanc3d]

Btw can you remember if there was a version that displayed the diffrent world time zones ?

[@grumich4084]

Ah pal, you wanna buy the "HP01" watch, in gold, of course. It was HP's only foray into making a watch and it was pretty darn cool. At the time I wanted to get one, but couldn't dig up the coin. Later, when I graduated from college and joined HP I worked with a guy who had one. Along with telling the time, it also was a calculator and a whole lotta things more. I found some on eBay, but haven't taken the dive.

[@InfernosReaper]

I feel kinda sad because my casio is just a watch with janky memo function and international clock.

[@jimmyzhao2673]

Maybe using a heat gun to soften up the plastic & glue would have helped ?

[@bowlingguy7755]

Wow! That's a truly impressive piece of tech from the early 1980s. Thanks for the video!

[@lcdconsultant5252]

Amazing tear down Dave. Thx

[@moofymoo]

back in 90' after soviet union collapse, having credit card form factor calculator meant you were instanty one of coolest guys in school. I wanted it so bad back then.. now I even want to get one. Better later than never :p

[@KrotowX]

Was curious though about what is inside of such thin calculator. Thanks about demonstration :) Got this calculator in mid-eighties as gift from distant relatives living at other side of globe. Used it in school for two years then sold it.

[@krnlg]

Very cool to see that chip! Great video.

[@alynicholls3230]

you should finish that calculator Dave if only for completeness, i would buy one. if you made them or got them made cheap enough you could print the back of the calculator as your business card, that would be cool.

[@londospark7813]

I'd love one too Dave - please please please finish the uCalc off!

[@Darieee]

I sure would love one too

[@balaclava351]

Based on what he said I think he did finish and even sell them. Just not any more .

[@Darieee]

Nah, he said that about the calculator watch

[@sirtoby2727]

C'mon Dave, I'd love to have one uCalc. Or two. Or more PLEEEEEAAAASSSSE

[@eeanas]

Your videos are always fun and nice to watch

[@sloth0jr]

This is one of your best! I'm fascinated by the backside of the flex PCB, as it looks like you partially uncovered some writing - Looks a lot like an NEC logo and something else. Outsourcing? I looked but didn't see a direct relationship between NEC and Casio. Could you remove more of the black material to see?

[@karlStuefer]

24:55 also has some "NEC" written on the chip

[@sloth0jr]

Good eyes!

[@kashiokyoiku9981]

Casio would almost always use NEC or Hitachi microcontrollers on their products, as they never had their own chip fabrication plant. (usually on the most innovative products NEC would manufacture the custom chips). Casio did have their own thin-film /PCB on film plant however so these products were perhaps just to show off what they could do. Most Japanese businesses have long term "alliances" with suppliers and contractors...the last thing they did was a mobile phone joint venture between NEC, Hitachi and Casio before everyone sold off the chip manufacturing divisions.

[@Andrew_Erickson]

I was really hoping this would turn out to be a sheet of paper.

[@karlharvymarx2650]

We had one of those when I was a kid. It came in a mostly black box and I think the name of it was "Polish Notation Calculator." Inside was a pad of paper and a pencil. None of that weird RPN stuff back then.

[@KuraIthys]

RPN is bizarre but awesome. Order of operations? Who cares! You don't need it, things happen exactly as written. XD

[@simontheconner]

This video really is a teardown. I'm not disappointed.

[@NetworkXIII]

Dave, great job as always, I really enjoyed the teardown. Years ago I integrated a basic parallel-plate capacitor into one of my PCB designs at work as an experiment, I think it measured out around 60pf with 8 mils of FR4 between the plates, which was relatively close to the value that I had calculated.

[@goamarty]

Long time ago I asked a colleague at the university who worked in a PCB factory if he could make me a PCB capacitor: 10 layers, square, 12cm edge length and a little more than 8mm thick (the maximum he could do) for high voltage experiments. The thing has about 5nF and is good for >25kV. It is probably the thickest PCB he ever made.

[@joea3728]

My nephew works for a major credit card company. a few years ago, he showed me a prototype for a new credit card. it was a fully functional calculator With a credit card chip built into it. And it may have had a few other bells and whistles built in. He wouldn't talk much about it. But it was an amazing piece of engineering. And yes you could put it in your wallet. We have the technology, we can build it, but do people really need it ?. Especially since it's built into your smart phone. Joe.

[@johnfrancisdoe1563]

Joe A A few years back another company made a fully functional credit card that had keypad for pin entry, LCD and battery. It also had electromagnets in the magstripe so it could dynamically change the content, thus allowing a chip based card design to work securely with existing magstripe payment terminals. They were hoping to sell millions to credit card companies, but the banks instead forced shops to upgrade to true chip terminals,while retaining the insecure magstripe for backward compatibility. I wonder if it's still possible to extract the pin from the magstripe for offline payments or if they at least blanked out that.

[@DAVIDGREGORYKERR]

A fast way to get into it's innerds is thinners will dissolve the casing and give you access to the inside.

[@edherdman9973]

Dave: Genius at tracing out circuits & identifying components Also Dave: Takes 5 minutes to realize the carbon pads are slightly lifted off the contacts xD

[@simio1337]

this video is nuts, your content is fantastic!

[@mik310s]

I had one of these when I was a kid and loads of the casino calculator watches that I wore all the way up my arm :D

[@garfieldnate]

Casio also makes the best electronic dictionaries. I wanted to work there when I lived in Japan but I heard the corporate culture could be pretty strenuous.

[@CapeCodCNC]

I had to go buy one on ebay while I was watching! Very cool!!!

[@PersonaRandomNumbers]

Wow! That's an incredible calculator. I really wonder what we could do today with the same sort of size -- achieving something like this back than is truly insane.

[@DamaKubu]

I enjoyed this video. This casio will stay much longer in internet than it would on its own.

[@PlasmaHH]

that gunk isn't transparent on top and black elsewhere, it is slightly translucent and just due to thickness appears blacker, which can be seen quite good where the frame vanishes into it.

[@trickyrat483]

Can't wait for the "repair" video. :)

[@NanoMine]

That is the most beautiful thing I've seen.

[@NICK-uy3nl]

This is 1984 technology. Japanese precision manufacturing is amazing. Great tear-down. Imagine if Casio were to build a 2 mm thick flexible smart phone today !

[@plaws0]

AND IT WAS MADE 35 YEARS AGO! HOLY COW. Really quite remarkable.

[@russellfroggatt]

Can't believe this was engineered in 1983. Amazing.

[@ecospider5]

Fantastic engineering thanks for letting us see that. The custom capacitors were just cool

[@JediBuddhist]

😂 Hahahaa Dave, I couldnt help noticing the pot calling the kettle Black (solder mask) So you don't hate it that much then.. LOL 😜

[@hal0eight]

I had a bunch of these and the SL-750 as a kid. They were great but the darn solar cell often cracked. It usually still worked with one crack, depending where it was, but it always got worse. Sometimes the LCD displays would go leaky as well. That said, I had a heap of them because they were just cool. It would break, and you'd just buy another one. Perfect business model.

[@thomheath2569]

at 21:00 the green film appears to be what we used when screen printing circuit boards, it is a dielectric ink that would insulate different layers of silver doped conductive inks creating a multi layered circuit entirely of inks. The black layer would probably be a carbon based ink. In a past life, I designed interfaces for membrane switches using printed circuits and formed metal domes

[@doctorazizli]

Loved all what I see here. Just is amazed with the great engineering. Well done, #Casio.

[@BlackburnBigdragon]

I used to have several of these. Back when I was in high school, it was always in my notebook. I also had one in my Dungeons & Dragons notebook. They were cheap, easy to carry and they came in handy.

[@LemonRush7777]

BlackburnBigdragon They are worth a lot now. Sell them.

[@BlackburnBigdragon]

Oh, I no longer have them any more. They either long ago broke and got thrown in the trash or lost to the ages. Haha! They were cheap. It's so funny how this cheap, crap, thing that was pretty much everywhere back then (all my friends had these things because they were cheap.), and now they're worth $$$$.

[@Colddirector]

And to think, just 40 years ago these were big bulky things that sat on your desk and had to be powered by mains.

[@MrQuantumE]

40 years ago was 1978, the first handheld/pocket calculators started emerging in the 60s

[@Colddirector]

It was my impression that desktop calculators were still fairly common throughout the 70s, though. But yes, handhelds started popping up in the 60s.

[@joinedupjon]

Hmm Casio fx31 came out in 1978 - it's basically the same footprint and weight as the current model fx83 (twice as thick) I love casio too but in a way 'peak calculator' has been and gone I think

[@thanthanasiszamp4707]

joinedupjon and to think that in 25-50 years from now, proffessional PC's will as small and as thin as this calculator!

[@KuraIthys]

The calculator wars were the direct predecessor to the home computer wars of the 80's...

[@bibasik7]

Apple: *furiously taking notes*

[@ultort]

It's funny, yesterday I measured the thickness of my (rfid) credit card and it is actually thicker that this calculator: from 1mm and up to 1.35mm on the chip

[@RolandElliottFirstG]

I have one of these stashed away somewhere, Japanese made i think , no other country could achieve this. Reminds me of the April fool page in ETI back in the 80's where they had a page dedicated to the worlds first thinest circuit board , it was printed on the page in ink inside the magazine. I have some very thin PCB's from the 1950's whice are thinner than this , they were actually hearing aid PCB's with miniture valves attached on a separate box , they are paper thin, made in England, some of them were prototype boards i have quite a few of them because my father worked in the Phillips industry in the design lab.

[@avejst]

Thanks for sharing 😀👍

[@loopshackr]

I have a Film Card SL-760 from about that time. 3.1mm thick (about 4 credit cards). Was a promo item for Maxell Corp. of America.

[@ThePropBender]

I am currently studying the field of microelectronics at VUT Brno and this video made me feel i have made good decision to come here.

[@VenturiLife]

For 1983 that's pretty impressive.

[@yasirnoori4848]

At 26:30, I don't think what you're seeing is different layers on the chip. You're seeing the structures at different focal points because some were under the coating and some weren't. The transparent coating blobs create different focal points like magnifiying lenses.

[@TheOnlyPsycho]

The initial part you removed also had the polarizing filter for the LCD.

[@Edu_RJR]

i wonder if they just used a regular chip and shaved off excess material to make it thin

[@ijabbott63]

In good old "Haynes manual" tradition, reassembly is a reversal of dismantling.

[@reggiebenes2916]

I can't believe they had LCD screens that thin in the early eighties. That's impressive how that was engineered.

[@peekpt]

what a beauty! Probably the chip got sanded in a precision cnc

[@ElectroTutoriales]

NEC logo @18:01?

[@tzisorey]

Haha, I remember having one of those. Had another, Casio I think, that was slightly thicker - but the keypad was transparent.

[@killymxi]

Dave, you could've shown more of the back side of the board in the video. _Please upload hi-res photos of the board at least._ I'm curious what is there behind "capacitor" things, and what's with the way they connected to steel sheet(s).

[@Quad5Ny]

Don't feel bad, you're documenting the construction for history and future products to use.

[@douro20]

There was the Casio FS-05 Film Watch, which is probably still the thinnest dual-time hybrid digital watch.

[@electronicartis]

good work eev

[@TheHuesSciTech]

Very cool! Please measure the capacitance of those capacitors? Also, you seem to have missed that the very topmost film also serves as one of the LCD polarizers.

[@johnfrancisdoe1563]

TheHue's SciTech And probably the layer that actually contains at least half the conductive segments, since it already connects to the board. They probably had the LCD factory simply extend the uppermost layer of the construction past the 2D size of the other layers.

[@douro20]

John Francis Doe They made the LCD in-house. They still make their own LCDs

[@andruloni]

I don't think you can measure those capacitors after the teardown

[@tongordebeke1355]

Please don't destroy those iconic calculators the are relics.

[@redtails]

I saw some writing on the DIE at 24:56 , but I don't think it says NEC

[@thomheath2569]

at 12:28 it appears that the screen printed ink has de-laminated from the front film carrier and is stuck to the pressure sensitive adhesive used to stick it all together.

[@PaulJosephdeWerk]

The green stuff on the back of the upper metal film is probably an insulation to keep the IC contacts from shorting.

[@BaneTodor]

Thank you for this.

[@richfiles]

This is a far cry from my SCM Cogito 240SR or my Friden EC 132... Those machines also performed the same functions, but they also weighed nearly 40 pounds (18 Kg)!

[@morelenmir]

I once took one of these apart when I was a child. Not very scientifically done though with a pair of nail scissors and tweezers. Obviously I couldn't see much but the things were almost magical in how slight and thin they were.

[@AL_O0]

Looks like they first built the board with the smd components and then milled the chip and the other caps down as much as they could. I think the green stuff might be to protect the components and don’t short out on the steel and to protect the silicon chip from just breaking

[@gabest4]

This is my Taiwanese knockoff, shameful 2.3mm thick (did not want to peel off the front, too): imgur.com/a/tjZg8kO Look at that soldering.

[@matsv201]

I use to have one of those to

[@SproutyPottedPlant]

Aaaah I remember that calculator, my Dad always had unusual calculators hanging around his wine shop.

[@mfx1]

It looked like the polarisor for the LCD was part of the front film you removed.

[@scottholmes4388]

Very interesting design. Everything about it was very 1980s. Like this was the pinnacle of engineering for its day.

[@illustriouschin]

Sqrt is a significant enough operation to be calling this a five banger.

[@BenHelweg]

I was thinking that too.

[@ArneSchmitz]

Naah. You can approximate sqrt by using iteration and the four other functions. ;)

[@renesolis2604]

I have my vintage CASIO calculator, with boxing game included ‘80. It works. Pre-Atari / ARM

[@timthompson468]

From what I’ve found heat does work much better when separating adhesive layers, as you suggested, especially if you want to get them apart intact. Of course that makes it harder to handle. I think you “got her done” though! Interesting. I saw a broken one on eBay for >$100.

[@EEVblog]

I would have used the heat if I wasn't making progress.

[@timthompson468]

EEVblog Yeah, I didn’t mean to sound critical. I was just affirming your comment about applying heat in the video. That was mainly for anyone who wasn’t aware how much easier it things come apart with a little heat. I got one of those 858D hot air stations after I saw your demo, and I use it for that, in addition to SMT soldering. I work in high voltage, and sometimes have to do failure analysis on potted modules. It’s amazing how a rock hard epoxy will just flake away like soft clay after the application of heat. The 858D is great for that. In a previous job, I had to remove safety labels when reworking old weather equipment. The labels were sunbaked for years, so they’d just flake off in tiny pieces when I tried to scrape them off, but hitting them with a heat gun, the adhesive would soften up, and they’d peal right off. Great trick.