CG20-JE

Hi there, thank you for stopping by. This project was largely inspired by the Ti 84+ KE, designed by noahkiser. I really wanted one and yet I'm most used to casio's calcs, so I remixed it and made my own :)

Buying Second Hand

If purchasing a CG20 second hand, buy a calculator introduced in production lines in March 2013 or after. Earlier models have a less vibrant screen where red appears more pink. (The CG50 also uses the newer LCD.)

You can see the differences in the comparison video (rev 04 on the left, rev 03 on the right): Screen Comparison. The new LCD is more vibrant and brighter overall.

Reading the Serial Number

Section adapted from WikiPrizm

The serial number can be used to deduce the year and month of manufacture. The format is:

mmmmmYMvAxxxxxx

mmmmm: Model. 755AW = fx-CG 10, 755DW = fx-CG 20, 755CW = blue “School Property” fx-CG 10, 810AW = fx-CG 50, 810FW = fx-CG 50 AU, 811AW = Graph 90+E.
Y: Last digit of production year (2008–2017).
M: Production month. 1–9 = Jan–Sep, X = Oct, Y = Nov, Z = Dec.
v: Version. M for fx-CG 10/20, Q for fx-CG 50 and Graph 90+E.
A: Appears to always be A on the Prizm.
xxxxxx: Sequential serial number.

Examples

755AW0XMA004579: fx-CG 10 — October 2010 — unit #4579
755DW14MA067642: fx-CG 20 — April 2011 — unit #67642

Bill of Materials

Total cost is around 350 CNY (~$50 USD) assuming a 3D printed top case rather than CNC aluminium.

You need:

Soldering experience and solder (plus all the usual prerequisites)
A certain degree of patience and pain
No exam within 5 weeks that requires your only graphing calculator
Whatever’s in the BOM — BOMCalc.xlsx

The screws from the original calculator can be reused to attach the top panel.

Testing

Press OPTN + EXP + STO + AC, then F1, 9 (your data is safe). Then press 3, 2.