Author Topic: EEVblog #389 - Casio Calculator Investigation  (Read 11205 times)

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Offline EEVblog

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EEVblog #389 - Casio Calculator Investigation
« on: November 21, 2012, 11:47:41 pm »


Dave.
 

Offline mickpah

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Re: EEVblog #389 - Casio Calculator Investigation
« Reply #1 on: November 22, 2012, 12:47:12 am »
want to see weird Calculator internals ?
MY HP 32E's man IC is not soldered at all ( still works 30 years later too! god am I that old ?)
http://www.keesvandersanden.nl/calculators/hp32e_repair_2.php
 

Offline EEVblog

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Re: EEVblog #389 - Casio Calculator Investigation
« Reply #2 on: November 22, 2012, 01:04:21 am »
Inside my old HP42S
No, I did not crack open that chip, that's how it is!


Dave.
 

Offline IanB

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Re: EEVblog #389 - Casio Calculator Investigation
« Reply #3 on: November 22, 2012, 01:21:55 am »
Hmm. We often think about having many layers on a complicated PCB. But how many layers on a chip? It must be just as complicated as a PCB inside there with all those terminals around the edge.
I'm not an EE--what am I doing here?
 

Offline Zad

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Re: EEVblog #389 - Casio Calculator Investigation
« Reply #4 on: November 22, 2012, 01:33:39 am »
Chris Gammell is the bloke to ask about number of layers in a chip. You might be surprised how few actual metallisation layers they have.



My fx-3600p in this photo draws a huge 68 uA! Vintage 1982 ish. But still on the original battery!

Offline EEVblog

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Re: EEVblog #389 - Casio Calculator Investigation
« Reply #5 on: November 22, 2012, 01:41:12 am »
Hmm. We often think about having many layers on a complicated PCB. But how many layers on a chip? It must be just as complicated as a PCB inside there with all those terminals around the edge.

As always, "it depends".
These calcs are not complicated and often contain very basic 4 bit CPU's.
Just like a PCB's, you'd be surprised at the routing density you can get with just two layers.

Dave.
 

Offline pickle9000

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Re: EEVblog #389 - Casio Calculator Investigation
« Reply #6 on: November 22, 2012, 02:16:51 am »
How many other words can be made on a calculator?
 

Offline jeroen74

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Re: EEVblog #389 - Casio Calculator Investigation
« Reply #7 on: November 22, 2012, 02:40:28 am »
That last calculator is not a Casio, it says Sanyo on the flex pcb (at 13:19).
 

Offline EEVblog

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Re: EEVblog #389 - Casio Calculator Investigation
« Reply #8 on: November 22, 2012, 03:05:57 am »
That last calculator is not a Casio, it says Sanyo on the flex pcb (at 13:19).

That's the solar cell. It's a Casio.

Dave.
 

Online tom66

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Re: EEVblog #389 - Casio Calculator Investigation
« Reply #9 on: November 22, 2012, 09:46:38 am »
I note that Casio seems like like Sanyo solar cells.

I had an FX 83-GTes with a dodgy battery contact causing the battery voltage to drop out.  Cause eventually was resolved by cleaning the terminals. The display would get really dim and the calculator -would- slow down calculation. If it dropped even further it would corrupt the display RAM with random data and usually the calculator would need a reset.
« Last Edit: November 22, 2012, 09:48:14 am by tom66 »
 

Offline robbag

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Re: EEVblog #389 - Casio Calculator Investigation
« Reply #10 on: November 22, 2012, 09:53:25 am »
Dave you are a kid at heart. I remember the days during school where you would write words on the calculator........BOOBIES
Clever.
 

Online AlfBaz

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Re: EEVblog #389 - Casio Calculator Investigation
« Reply #11 on: November 22, 2012, 01:41:07 pm »
Quagmire from family guy likes calculators to

Calculator Boobs
 

Offline jeroen74

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Re: EEVblog #389 - Casio Calculator Investigation
« Reply #12 on: November 22, 2012, 01:42:48 pm »
together with a friend I once made a list of words you could make, we ended up with over 110 words or so.
 

Offline Stephen Hill

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Re: EEVblog #389 - Casio Calculator Investigation
« Reply #13 on: November 22, 2012, 01:54:11 pm »
 

Offline Ketturi

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Re: EEVblog #389 - Casio Calculator Investigation
« Reply #14 on: November 22, 2012, 05:21:50 pm »
It would be interesting to see follow-up video about comparing those old photocells to cutting edge technology, and to normal new calculators to see how much solar power technology have developed. I think that power consumption have gone down, and not the photocells, but we have also battery charger etc. using solar cells so I'm not 100% how they work, does they have higher cell voltage and efficient switch mode converter to produce higher charging current or what?

I had similar calculator as the last calc shown in video, brilliant device. I also took it apart when I got it, very interesting construction. It's photocell couldn't power it in classroom and without battery it were useless. Then I bought TI-92 which I'm using still at this moment, sucks battery 8mA when idling and 40mA doing some processor intensive calculation! Always crying backup batteries in my schoolbag :P
Ketturi electronics: http://ketturi.kapsi.fi
 

Offline Matje

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Re: EEVblog #389 - Casio Calculator Investigation
« Reply #15 on: November 22, 2012, 07:28:54 pm »
The weird mounting of this chip is probably just a variant of "flip chip" mounting. It seems this technique is quite old, Wikipedia says IBM did it in the 60ies. The yellowish gunk with the bubbles in it is probably the "underfill" needed.

In a way flip chip is like BGA, just with the expensive chip packaging left out.
 

Offline marcel.o

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Re: EEVblog #389 - Casio Calculator Investigation
« Reply #16 on: November 22, 2012, 07:49:52 pm »
I saw the vid and didn't know it could be that interesting!!


But look what I found in my drawer..




And it still works!!

1 Chip (week 49 1976!!)
1 dc-dc converter for de vfd
1 valve like 9 digit vfd

would be fun to measure at some points.. (some slightly high voltages for the tube enz.)

 

Online jancumps

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Re: EEVblog #389 - Casio Calculator Investigation
« Reply #17 on: November 22, 2012, 09:53:44 pm »
A quick Google found this list of 250 words:

http://paperlined.org/apps/wikipedia/offsite_content/Calculator_spelling.txt

They forgot a few dutch words like
BLOESLOS
LESBIS
and the calculation LOL + LOL = HIHI
 

Offline LaurenceW

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Re: EEVblog #389 - Casio Calculator Investigation
« Reply #18 on: November 22, 2012, 10:18:46 pm »
Dave, surely that is an early form of BUBBLE MEMORY?  :-DD

I'll get my coat
If you don't measure, you don't get.
 

Offline EEVblog

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Re: EEVblog #389 - Casio Calculator Investigation
« Reply #19 on: November 23, 2012, 12:45:44 am »
Dave, surely that is an early form of BUBBLE MEMORY?  :-DD

That one, Sir, I will pay!  :-+
Wish I'd thought of it at the time  |O

Dave.
 

Offline G7PSK

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Re: EEVblog #389 - Casio Calculator Investigation
« Reply #20 on: November 23, 2012, 04:09:33 pm »
Very interesting video again, Made me look out my Casio that I bought in 1975 or 1975 and take it apart, it still works the only thing that is that the leatherette pouch has disintegrated long ago but the cardboard box and instruction sheet survive I tried to find the invoice but to no avail, I know that I purchased it from Heffers book shop stationary department in Cambridge 1974 or 1975.   
« Last Edit: November 24, 2012, 04:09:38 pm by G7PSK »
 

Offline And!

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Re: EEVblog #389 - Casio Calculator Investigation
« Reply #21 on: November 23, 2012, 07:31:25 pm »
Maybe it would be interesting to put current variation on oscilloscope,
and find out how calculation is affect on current consumption variation ?
(Power-Analysis Attack  ;) )
« Last Edit: November 23, 2012, 08:37:13 pm by And! »
 

Online tom66

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Re: EEVblog #389 - Casio Calculator Investigation
« Reply #22 on: November 23, 2012, 08:30:57 pm »
Casio fx-83GT+

VPAM one -- waiting for the hate mail!
 

Offline marcel.o

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Re: EEVblog #389 - Casio Calculator Investigation
« Reply #23 on: November 23, 2012, 09:10:26 pm »
Very interesting video again, Made me look out my Casio that I bought in 1975 or 1975 and take it apart, it still works the only thing that is that the leatherette pouch has disintegrated long ago but the cardboard box and instruction sheet survive I tried to find the invoice but to no avail, I know that I purchased it from Heffers book shop stationary department in Cambridge 1974 or 1974.
 

Online tom66

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Re: EEVblog #389 - Casio Calculator Investigation
« Reply #24 on: November 23, 2012, 11:32:41 pm »
Interesting -- Was playing around with my calculator.

Shift+7+ON activates diag mode. Press 9 to go through display test. Press Shift five times to get to version screen and note "Pd-" as the option.

Pencil in using a graphite pencil one of the Pd1..7 options, and activate the same version screen... and see "PdN" where N is the one you penciled, or a "?" if you pencile more than one.

However... despite doing this, I don't notice any difference. I think I need to reset the calculator to enable the extra options. The "Internet" reports that P4 on older Casios makes a low-end one behave like the 991ES with the differentiation/integration/solve features.
 


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