Sharp EL-840G calculator Teardown

ID: 192614

Description: A business calculator from sometime in 1992.

Steps:

1. This is a sharp EL-840G business calculator from 1992. It is part of my small calculator collection, which I am now taking apart and putting the teardowns on Ifixit.
2. I don’t remember where I got this calculator, but at least it came with the original instruction manual.
3. This calculator also has 7 different functions, and is designed for business.

4. To begin disassembly, remove the two screws from the metal case.
5. Keep track of the screws! They are small and could cause potential injury if stepped on!

6. Once the two screws are removed, carefully lift up on the lid of the calculator. Next, on the inside, there is a plastic cover on the PCB. Lift up on this cover to fully expose the PCB, so you can see it.

7. The PCB is very simple, with only a small microcontroller, and a few diodes. The only other components are the LCD screen, and the solar panel, which also is connected to an optional lithium coin cell battery.
8. I would provide identification for this chip, but It only says “JAPAN” on it, so I can’t find anything about it. But I now know that it is from Japan.