Upgrade Your Casio Fx-82es Into 115es/991es/570es




The circuits of Casio fx-*es series are almost the same, except the mode selection part.  So you can upgrade your calculator by modifying the circuit.

I am Chinese and I edited these photos for a local forum. So please ignore Chinese characters on the photos.

This method is available for casio fx-*es calculators. NOT MS or ES PLUS series.

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Step 1: If You Are Lucky

Check the version of your calc.

The version is marked on the back of the calc. you can see a letter in a small circle which is at the top-right corner of the rectangle that has text in it.

If the letter is A, you are lucky.
Just open the calc, find the P4 jumper on board, fill the gap with pencil.
Then turn on your calc, see if there are 8 modes available.

If the letter is B, see the following, it is difficult to upgrade, but it is possible.

CAUTION: The success rate seems be VERY low. About only 20% can do it without experience. It is easier to do it with a magnifier.

It will mostly affect the display(too dim, strengthen ) if you fail.
or just not able to turn on.


Step 2: Position the Chip

extend the line that is 75 on it, scratch a mark with a knife.
then place a ruler like the photo, there is about 1.2 cm from the reference to the chip.

mark a cross on the chip.

connect the reference to the destination then mark it on the bonding

Step 3: Dig the Bonding

dig it with a knife like the photo.

keep the trace narrow.

you NEED a magnifier, or it is very easy to be broken.

The mode will switches to P- if you cut the line between the chip and the board. You can fix it with a pencil if you want to give up. but it isn't matter if you want to upgrade.

P- only have 3 modes, but it can do calculus, SOLVE/CALC, sigma, but no natural display.

Step 4: Change the P* Pin

when you reach the border of the chip, you must be VERY careful.
clear the bonding on the chip until you can see the reflection of the chip.
ONLY need a little.

draw on the chip border with a pencil.

Step 5: Finishing

turn on your calc, press shift+7+on, press shift until the screen shows ROM 018 MODE P*
if it is P- or there is only 6 modes or 4 modes, try broaden the exposing length of the chip especially on right, then smear it again.
If it is P0 or P4 or P? with 8 modes available, you are done.

the keys are remapped as the 991, eg. the Abs key in 82 is CALC key in 991.

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18 Discussions


4 months ago

Good information.


5 years ago on Introduction

The first method works well on my fx85-es !

By now it shows all the 8 menu points.

Thank you for sharing all of this !


7 years ago on Introduction

I just wanted to mention i have the fx-82ES with the A motherboard and the jumpers are labelled with D not P. And when i "jump" D4_1 it works. Thanks for the tutorial!


8 years ago on Introduction

Cutting a wire or pulling out a jumper seems an awful lot easier than this...



8 years ago on Step 4

hi i have a 82 es and im trying hard to convert it to a 911es..after digging the trace i dont know what to do?where is the P* pin?please help.


8 years ago on Introduction

hi mmm,, i did all as you said,, but when im gonna use it it doesn't do anything,, would you can help me whit this problem?? i really need the calculator ... i hope you can


9 years ago on Introduction

I'm one of the administrators from Fx-ES(MS) calculator forum,too. English version of the article in the photos are small. If you prefer, you can look to the Chinese forum. Welcome ~ (Chinese forum address:http://fxesms.5d6d.com/thread-2820-1-1.html) Another word of warning: most frequently upgrade is P-mode. Good luck


9 years ago on Introduction

I'm one of the administrators from Fx-ES(MS) calculator forum. This guide is only for Ver.B ROM 18 ES Series. This is called hardware upgrade(maybe hardware modify? I'm not sure...) in our forum and "硬改" in Chinese. The ES series are easily divided into 82ES, 991ES and other models by a jumper. This jumper were easy to modify in the past few years. (Can you see C(Canceled?)P0, CP1, CP2 and other contacts on the PCB of your ES(Ver.B)? They were connected with the CPU in Ver.A. You could change the P-value(P means program) in the self-check screen by connecting these unconnected contacts.) If you have a Ver.A 82ES and it's ROM 18, you can upgrade it in an easier way with no danger. ROM 21 ES calculators have no 991ES programs inside. So it's impossible to upgrade ROM21 calculators (software/hardware). We have been looking for a better way to hardware upgrade for a long time. But the probability of success is still very low. My old Ver.B ES was nearly damaged many months ago. Luckily, I found a Ver.A and bought it. I successfully modified it into P0(991ES). Now I use Nspire CAS... P0---991ES Fraction format: d/c P4---991ES Fraction format:a b/c P3---82ES Fraction format:d/c P7---82ES Fraction format:a b/c ... P? means more than one P contacts are connected. Modes in menu are depend on contacts you connect P- means no P contacts are connected. It's a very special mode. Modes:3 Output format:decimal Keyboard mode:991ES(That means you can use 991ES' programs which are in Comp mode) There is a complete chart about P modes on our forum but I can't find it now. Sorry. If I find it, I'll translate it into English and send it to this forum. Sorry for my bad English :p

1 reply

Reply 9 years ago on Introduction

thank for your advice.
I will update this post on weekend.

this is my post on a local forum(Chinese): http://fxesms.5d6d.com/thread-2820-1-1.html
there are more photos that can explain it.


Reply 9 years ago on Introduction

There's a blob of black resin covering the CPU. He's describing how to pick off the black-stuff to expose connections on the CPU. If you bridge these with (conductive) graphite successfully, it changes the way the machine functions.



9 years ago on Introduction

Could you explain exactly what this is doing?
It seems to be advising a graphite-bridge on the CPU, which you locate with a ruler... I'm struggling to get my head around this working.


5 replies

Reply 9 years ago on Introduction

yes, there are 8 mode selecting pins(P0~P7) and a ground pin(P-) at the border of the chip.
When the P- is connected to any one of the P0~P7, it shows the selected mode on the self-check screen.
when more than one pins are connected, it shows P?, and the function depends on what pins you are connected.
But the P0 is the closest pin to the P-, so it is most easy to connect.
P0 is for 991ES/115ES/570ES, and P3 is for 82ES


Reply 9 years ago on Introduction

So they cost almost exactly the same amount of money to produce, but they add a "jumper" for the more advanced device?
Could you put a difficulty level on this, that is % probability that the average person will break the machine vs enable the modes - it looks risky for someone other than yourself who is obviously skilled and knowledgeable.



Reply 9 years ago on Introduction

it is VERY difficult. There were only about 4 persons did it on my local forum.
And i don't know how many had failed, i think it is about 20.

But i tried twice and succeed twice. it may be easier to use a good magnifier. I used a 25x one.


Reply 9 years ago on Introduction

Well done then. You've given me the level of difficulty I had expected.

Thanks again



Reply 9 years ago on Introduction

The difference between 82es and 991es is exactly a jumper.

The jumper in the earlier version A is on board, so it can be easily upgraded.
But CASIO fixed this problem in ver B. Then the jumper is hid in the bonding.