Unlocking Casio fx-82ES to Casio fx-991ES

CA50 · 27-12-2011, 02:14 AM

This is a guide to unlock your Casio Scientific calculator to a higher version with more features.
I have tested it with my own fx-82ES and it worked.

This mod will unlock model number fx-82ES/83ES/85ES to fx-991ES
Generally 82ES comes with 249 functions function and when the "setup" button is presses, only 3 functions are listed, whereas 991ES comes with 403 functions and when the "setup" button is presses, only 8 functions are listed, by this you can differentiate between the two

Steps:
1. Check what version you have - on the back, just above the made in China sign, there is a letter in a circle: if it’s a B, unlucky because you can’t do the mod, however if it’s an A you can.

2. Open up your calculator - on the back there are six screws, using a Phillips screw driver, remove these and then lift off the back, revealing the circuit board.

3. Find the P4 jumper - on the circuit board there are six screws, between the middle two is a little white P4, to the right of this is a small split silver circle. Take your graphite pencil and colour this, making sure the whole thing is covered.

4. Put it back together-now put the back, back on and screw the screws into the holes.

Original Setup Screen

After Unlocking

Please share your result. Please note that i will not be responsible if your calculator goes kaput.

Source:
Modding an fx-82ES/83ES into a 991ES - YouTube
hackear calculadora casio fx-82es - Taringa!
How to upgrade your fx-82es, fx-83es and fx-85es to a fx991es - The Student Room

CA50 · 29-12-2011, 05:30 PM

Anyone tried this trick ??

**MetalheadGautham** · 30-12-2011, 01:24 AM

This works but has some issues. The buttons labeling around number keys for alternate functions does not change so users may be confused. And these days lots of B models are present.

Considering most FX-991ES usage is by engineering students writing their term exams, few 100 rupees to avoid confusion during exam is justified