EEVblog

A look at the amazing construction techniques used in the world's thinnest calculator by Casio
Destructive teardown on the Casio SL800 credit card calculator from 1983.
It's more interesting than expected!
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[@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

[@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.

[@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!

[@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?

[@Sparks52]

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]

​@@Sparks52well... visit any German school. You'll find at least one.

[@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.

[@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

[@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.

[@pentachronic]

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.

[@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

[@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!

[@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

[@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

[@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.

[@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.

[@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.

[@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

[@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 :-)

[@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.

[@jsmith5052]

Those button pads look like force sensing resistors, which are quite cheap. I imagine the bottom pads don't actually need to sit above the pad but rather the pads are just for overall feel and to more equally distribute the force of your finger to not warp/damage the pad overtime which will cause the button to fail on. There's probably a threshold resistance that triggers a 'touch' of the button. A lot of digital scales use the same thing. www.digikey.com/product-detail/en/adafruit-industries-llc/166/1528-2335-ND/7393589

[@atmel9077]

Wow. It's a pity you destroyed it but it's a masterpiece of engineering! You cound send it to Electronupdate or Deus Ex Silicium and they cound analyze the chip.

[@Edu_RJR]

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

[@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

[@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

[@jimmyzhao2673]

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

[@jeetlodaya775]

That chip hurts my brain !

[@oniruddhoalam2039]

Same

[@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. ;)

[@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.

[@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.

[@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!!!

[@trickyrat483]

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

[@First2ner]

That IC looks like it was drawn on there

[@gaboaaa23]

Ok, the wath arrived! Put a new battery in and it works(old battery was put in upside down...no wondern it didnt worked :)))) ) Everything works except the calculator touch pad. TV remote ect all is working but not the calculator. I had this before on another casio calculator watch, where ive replaced the battery and some kind of "black rubber/plastic" piece flew out of the watch housing. I didnt knewed how or where to place it and from there on the touch pad never responded anymore. Here on tis TV watch i hadnt seen this "black piece"! Should there be one? Or what else could be the problem, that the touch pad dont respond? Ive did the AC reset succesfully and the watch showed 12:00. Thanks

[@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.

[@tullgutten]

That chip has less depth than a 2D image . Alien technology

[@germimonte]

why did this got discontinued, sure, smart phones, but back then?

[@cup_and_cone]

Everything I've read suggests it was two things: It was mostly a novelty (hard to read, hard to push right button, etc) and not very durable. It's not something would've taken out to do your taxes with.

[@johnfrancisdoe1563]

thechosendude But it would be great to keep in your wallet for calculating prices etc. while shopping.

[@matsv201]

"why did this got discontinued" Probobly because of wafer sizes. In the 80-tys and 90-tys they made wafer sizes larger and larger to fit more circuts on the same wafer to make the process cheaper. Because the wafer would be to flimsy to haveing a very thin 300mm wafer they also need to make them thicker. The earliest wafer was 0.27mm thick. But alreddy in the early 90-tys they was up to 0.5mm, and by the late 90-tys they was 0.78mm thick

[@marijnl]

couldn't you just look at the shelves where the prices were on? Or the price stickers on products?

[@jusb1066]

the sl760 was a tiny bit thicker but was made into 1989, i bought a couple back then

[@tongordebeke1355]

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

[@jasonbrindamour903]

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

[@lcdconsultant5252]

Amazing tear down Dave. Thx

[@Gleb2]

“Repairability 0/10”. -ifixit

[@ElectroTutoriales]

NEC logo @18:01?

[@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.

[@bibasik7]

Apple: *furiously taking notes*

[@simpleton6813]

Hey Dave, do you sell the μCalc? I really want one!

[@EEVblog]

Nope, sorry.

[@migsvensurfing6310]

Simpleton After 9 hears its still not finished.

[@peekpt]

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

[@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.

[@miro2424]

That chip IC been shaved!

[@todesgeber]

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

[@TheDefpom]

I was horrified to see a collectable working calc be destroyed 🙀🤬

[@DAVIDGREGORYKERR]

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

[@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!

[@redtails]

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

[@zero3609]

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

[@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.

[@krnlg]

Very cool to see that chip! Great video.

[@Veptis]

With the wallet movement of 10 years ago, getting a calculator next to my magnifying glass and compass(with solar clock) would be a nice useless tool to have in my pocket. EDC

[@EEVblog]

"Wallet Movement"?

[@sakelaine2953]

It was a weird fad where people would try to hide entire wallets in unmentionable places. Often it would require a movement to recover the wallet. Just kidding.

[@marijnl]

was the wallet movement not the idea that everything must fit in a wallet? Like small tools, measure cards, en telephones with a large wallet :-)

[@InfernosReaper]

Between the calculator and the weird wallet multitools, it'd be a helluva wallet. However, it's 2018 and I think we should be able to do better than calculators on that scale

[@NaoPb]

I have a credit card sized USB stick.. it's a bit thicker though.

[@ZwiazeCie]

what a chip... amazing!

[@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.

[@redtails]

How the hell did they make this in 1983?

[@Quad5Ny]

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

[@optroncordian7863]

STOP! THESE! DESTRUCTIVE! WINDOWS! UPDATES!!! I would advise everyone turning off automatic updates in windows control panel! That way the world will become more calm and peaceful. Offtopic, I know. ;)

[@DavidLindes]

30:28/30:37 - yeah, I miss my fx-7000G graphing calculator, too. Granted, it was much much thicker and bigger than this... and I’m sure by modern standards would be painfully slow (I think I remember having to wait for it sometimes, even), but... I just liked it. Liked the UI, etc. I fanboy with you. :D

[@robinwilson-sauls9891]

PLEASE!!!! Stop with the "BOYS!" Females are here, watching/learning! Your not alone in a "BOYS" Club! Thanks!!!

[@Treveliian]

You might need to uninstall the Windows Update KB4074588 to fix your USB drivers..... atleast that was the fix about a month ago for several of my clients USB devices not working after said update. I had to Remote into the machine to do it as none of the peripherals would recognize. google USB devices may stop working after installing the February 13, 2018 update (KB4074588)

[@battleangel5595]

These Windows 10 updates seem to bring me back to the 7 hours I wasted running Windows ME... When I bought my first shredder the first thing I ran through it was my Windows ME disc. I spend hours decrapifying my PC, only to have the same [REDACTED] installed again and again...

[@233kosta]

"Windows 10 did an update"... Yeh, they fuck my laptop further and further EVERY SINGLE TIME they do that. It's been going downhill for 2 years already, now it's nearly unusable. Time for a downgrade, me thinks...

[@metricruler1876]

In the early 70s most accounts departments still used a mechanical calc called a comptometer. In 1973 the sinclair calculator appeared as either 4 function or a scientific kit version costing £20 ish (I was paid £14). Things moved quickly and in 73 my lecturer turned up with a box of Casio 9v LED scientific pocket calculators with option for an addition of a mains PSU (a battery cost £1 and lasted about 4 hours). Never looked back from then. By the end of the decade I was "driving" a Spectrum and got my first 80286 in 1990 for an eyewatering £2000. To see this clown killing yet another link with those days just hurts almost as much as having to listen to his annoying whiney voice

[@TimeBandit68]

At 24:57 is a text. If you scratch that off, maybe a little secret will come to light ;)

[@Toenail83]

Great video Dave. I'll join the forum soon, after finals. You mentioned the Windows update problem. You might want to try the Linux route. Set it up on another PC and get use to it before you use it as a main OS. I'd suggest Fedora/CentOS then move to Arch Linux. Maybe try Ubuntu, but I've never had any luck with Debian based distributions. Fedora has certain lab distributions, maybe the science one will work for you. labs.fedoraproject.org/en/scientific/ Also if you go the Linux route, learn the essentials from the Red Hat Certified System Administrator exam. Even though it's for the exam, a lot of the stuff is imperative to becoming fluent in the Linux OS. I'll try and make some videos over the summer. www.certdepot.net/rhel7-rhcsa-exam-objectives/ With the green film, it might be a transparent conductive film. Also known as ITO (Indium Tin Oxide). I haven't found the history on ITO to date back to the SL-800, but I only looked for a few minutes so don't quote me on that.

[@myami3733]

+EEVblog *hey dave, got a tip that might help with your windows 10 issues.* don't know if you'll ever read this, but here goes. *1)* go to device manager. *2)* go to to "universal serial bus controllers" *3)* see if you can spot your "high speed usb 3 card". if not just do the following steps to all usb 3 devices. *4)* you must make sure the usb device is selected for the next step. *5)* go to "view" and select "view device by connection". *6)* you should now see a tree showing a "USB 3 root hub". right click and uninstall it. if prompted to remove drivers for disk select 'yes'. *7)* reboot, and this should fix the issue. if you actually did this and it work, i would be chuffed!! good luck.

[@johnsnow5305]

Heck, even today I think a credit card sized calculator could be useful. I mean sure, your phone has this function, but that times up a lot more space and time to get into the program. Especially if the credit card sized calculator only cost $2 - $5. I didn't know these even existed until your video. I have a TI-36x Pro since my graphing calculator stopped working and I'm happy with it - just not willing to bring it along with me everywhere I go lol.

[@buttholeChecker]

I still wear my casio calculator watch, people are always laughing at me.

[@Godzilla941]

I always wondered if someone could actually make a calculator that thin. Now I know. :) Also, any computer I use to actually get work done runs Win 2K, XP, 7 or Linux. Win 10 is about as brain damaged as it gets.

[@Grimeaper]

Might want to check your task manager as well to see if you caught the bug where WmiPrvSE.exe grabs your CPU by the balls and runs with it. I recently got that bug it runs from 50 to 70 percent of my CPU at all times. I tried fixing it how the people online said to fix it, to no avail. I had to download another task (no matter what you cannot end it with the default task manager and even going into your computer and mash turn off doesn't do it) manager so I can suspend it while working on stuff. If your PC gets slow just for no reason check for it. It is a nightmare when you a 3D artist. People think 3D artist therefoer GPU but no most of it is CPU hungry. Funny side note no matter what you get that allows you to uninstall windows app it will reinstall pretty much instantly it is annoying because I find it useless. Games and other crap always returns I think I still have Candy Crush even though I uninstalled it.

[@jam99]

But Windows 10 is the best ever I am told. How could it have messed something up? Nah, I don't believe it. It's really good; so good that it knows best what you should do with your computer. Microsoft knows best. If an update stopped something from working then it must mean you shouldn't use it. You should thank them.

[@borayurt66]

Yeah, I know... Don't turn it on, tear it apart... but this one made me cry... I had one of these back in the day and it was brilliant. It stopped working one day, I must have bent it or something... Now I'm gonna check ebay to see if anyone is selling a working one like this... Shame you destroyed that one.... Edit a few minutes later: No, there are none for sale... :-( You may well have destroyed the last working one... :-(

[@movax20h]

It actually has square root. So it is five banger I would guess. The chip is relatively complex. It has some memory / ROM, probably lookup tables for square root, and few registers to run iterative algorithm to solve square roots.

[@Crazytesseract]

How are the numbers stored and processed inside the chip. Are they stored as plain binary, or BCD? And is the addition/subtraction binary or bcd? How is multiplication and division done? I know is a keypad encoder, and and a binary to 7-segment convertor. I'm curious, can anybody please provide a hint?

[@JerryEricsson]

Love the Casio devices, used to have quite a collection of Cassiopeia PDA's that I used to watch videos on, and once had the Casio Data-Bank credit card in a small leather case. This was pre-cell phone era and I used it as a phone book for use with our huge brick police radio phones. Sadly it seems it was not X-Ray proof, as I had it in my police jacket whilst having to hold down a drugged up felon who was stabbed and needed a series of X-rays to see the damage the blade had done. After being exposed to the X-rays the device never again booted up, even when replacing the very thin batteries.

[@Acecool]

I was skipping around a bit and heard you couldn't find any writing... At the bottom of the memory array I saw NE maybe D and some other characters covered by the soft gunk... Edit: Also the paper on the top shim looks like it was there to prevent arcing ie an insulator... The soft gunk for the chip was likely to prevent shattering of the die if it was dropped ie vibration resistance.. the black hard plastic was a way to ensure the chip didn't move but also to insulate the leads - it looks like the normal plastic stuff they cover chips with, but much thinner - could that be? The key in the plastic / black stuff seems to be present except it looks like it almost goes directly down to the chip / die...

[@SuperFriendBFG]

Hey, is it possible that it's actually the PCB portion of the button that is slightly concave instead of the rubber/carbon pad? EDIT: Kept watching, I wasn't too far off base at least. :D

[@fleksimir]

Speaking of calculator construction, sharp has many models with superior construction. Most notably a thick hard plastic over the display, making it very easy to clean the dust and extremely hard to damage the display (most useful with kids handling calculators).

[@DrathVader]

It's the one video where we could use a quality microscope and that's when Windows 10 decided to fuck up updates. I'll be sticking with Windows 7, thank you very much.

[@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)!

[@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.

[@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).

[@carlossantiago4845]

The chip is attached using a technique known as TAB (Tape Automated Bonding). Checkout this video kzbin.info/www/bejne/jmKTZZ2Ag7mpq8U

[@markus8282]

I´m still traumatized from watching this poor little calculator dying. I clearly remember seeing them arranged in an electronics shop back in that days. When I saw them I could not believe that they can work with that skinny form factor. I can not really remember the pricetag, but they were not displayed in the department for cheap things, but prominently placed in the premium section. Rather than acquiring one of them I was more in for getting my first radio tape recorder, which I still have in working condition after all that decades.

[@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.

[@okaro6595]

I had one in 1985-86 but I lost it while I was in the army. It was 200 marks back then adjusted to inflation it would be 66 € now and adjusted to wages 111 €.

[@JohnRunyon]

My dad had that Casio calculator-watch for the longest time... that thing was amazing, but the buttons were way too small to be realistically usable with a finger. Even as a kid I couldn't use it with my fingers.

[@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

[@rsattahip]

Should have kept Windows 7

[@davids5148]

Haha bobby dazzler?! I doesn't now what the term was (holland) butt now i understand en.wikipedia.org/wiki/Bobby_Dazzler this is the best youtube channel ever!

[@WacKEDmaN]

amazing they could fit all that into a credit card size...especially for the 80s...give me ideas of making a credit card bitcoin wallet, that actually works as a credit/debit card

[@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

[@monchiabbad]

They had to add to the thickness to have the buttons, can you imagine if they used capacitive button.. Anyone up for paperthin keyboard calculator?