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Casio fx-3800P scientific pocket calculator
05-05-2016, 05:12 PM (This post was last modified: 05-05-2016 05:20 PM by jebem.)
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Casio fx-3800P scientific pocket calculator
Got this machine in a lot of other models from a flea market.
This looks like one little brother of the more powerful Casio fx-4000P.

Made in mid 80's. No way to know a date for sure as there are no date codes in any internal component.

Forensics result as displayed: 9.000015718
(Degrees mode. 9 sin cos tan atan acos asin)
I didn't try to get the extra digits, hence the different value from the rskey reported value.

[Image: Casio_fx-3800P_002.jpg]

Enter BaseN Hex mode and get the 2's complement of FFFF
Result: FFFF0001

Then go to BaseN Dec mode.
Result: -65535

[Image: Casio_fx-3800P_003.jpg] [Image: Casio_fx-3800P_004.jpg]

Low profile pocket machine typical of Casio of that era.
Single 3V CR2025 battery cell.
Undo the six steel screws to remove the back cover.

[Image: Casio_fx-3800P_007.jpg] [Image: Casio_fx-3800P_010.jpg]

Back label contents:
Casio fx-3800P
DC 3VDC 0.0005W
Use Battery 3Vx1
Made in Japan
Casio Computer, Ltd.

Declared power consumption of just 0.0005W (500μW and a current of 167μA). I didn't check these readings.

[Image: Casio_fx-3800P_009.jpg]

The On-Off switch will get lose after removing the back cover and should be stored for later reassembly.
Undo two extra screws to remove the PCA.
The LCD display assembly is attached to the PCB and it is not glued to the front panel. It is maintained in place by a foam that is pressed by the back cover.

One interesting note on the LCD assembly: The LCD itself is glued to a heavy metal frame. Not sure what was the engineering reasons behind this design choice. Most probably to give extra rigidity and protection, while giving the calculator more mass/weight for a more customer satisfying experience ?

[Image: Casio_fx-3800P_011.jpg] [Image: Casio_fx-3800P_012.jpg] [Image: Casio_fx-3800P_013.jpg]

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Casio fx-3800P scientific pocket calculator - jebem - 05-05-2016 05:12 PM

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