EEVblog #1078 - World's Thinnest Calculator Teardown!

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

[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

[LazerLord]

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

[richardincam]

I am really looking forward to the reassembly video

[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!

[gertnutterts]

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. ;)

[jonathanfadden]

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.

[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 :)

[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 YouTube with the name: Japanology Calculator.

[KRAFTWERKK]

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.

[fabimre]

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

[raleighsexton]

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!!!

[reggiebenes]

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.

[sheadjohn]

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

[gamingwithkendirk]

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

[pdrg]

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

[danweecc]

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

[zero]

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

[jasonbrindamour]

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

[JMacQ]

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!