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Casio FX991EX
07-15-2018, 04:51 PM (This post was last modified: 07-15-2018 05:12 PM by ijabbott.)
Post: #21
RE: Casio FX991EX
(07-15-2018 11:51 AM)Albert Chan Wrote:  My Casio FX-115MS had a dead battery, but still work under good light.
The back is somehow stuck even with all 3 screws removed (glued stuck ?)
Cannot replace battery without breaking the calculator ...

Mine has 5 screws - 2 on the bottom edge, 2 near the middle, and 1 near the top. But yes, the case still seems to be stuck at the top after removing those screws.

EDIT: I got it apart with a bit of gentle "persuasion" with a spudger. It just seemed to have a bit of sticky junk holding one edge together! Also be aware that you need to slide the back upwards slightly to unclip it from the top edge.

At least for the EX, you only need to remove 1 screw.

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07-15-2018, 04:58 PM
Post: #22
RE: Casio FX991EX
(07-14-2018 08:48 AM)ijabbott Wrote:  
Quote:And, not just "shown" result, but it's full precision values ?

Just the shown result. It's basically just a textual copy and paste operation.

Not sure about the model TI you're referring to (I don't have one of those) but the TI-89 and friends can use ans(3) to get a full precision version of the 3rd result up in the history, for example.
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07-15-2018, 05:04 PM (This post was last modified: 07-15-2018 05:14 PM by ijabbott.)
Post: #23
RE: Casio FX991EX
(07-15-2018 04:58 PM)grsbanks Wrote:  
(07-14-2018 08:48 AM)ijabbott Wrote:  Just the shown result. It's basically just a textual copy and paste operation.

Not sure about the model TI you're referring to (I don't have one of those) but the TI-89 and friends can use ans(3) to get a full precision version of the 3rd result up in the history, for example.

I was referring to the TI-36X Pro or TI-30X Pro MultiView (they are the same model, apart from the name). It doesn't have anything like ans(3).

Some Casio calculators such as the fx-115ES have a 'PrevAns' function to get the last but one answer.

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07-15-2018, 05:39 PM
Post: #24
RE: Casio FX991EX
(07-15-2018 04:51 PM)ijabbott Wrote:  Mine has 5 screws - 2 on the bottom edge, 2 near the middle, and 1 near the top. But yes, the case still seems to be stuck at the top after removing those screws.

EDIT: I got it apart with a bit of gentle "persuasion" with a spudger. It just seemed to have a bit of sticky junk holding one edge together!

Sorry for the mis-information, my FX-115MS had 5 screws too.

Per your advice, I "force" it open (almost breaking the thing).

Bits of Green junk is around the coin battery, voltage = 1.13 volt.

Contacts cleaned. Battery replaced, THANKS !

FYI, DollarTree store sell LR44 batteries, 4 cells for a dollar
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07-15-2018, 07:53 PM (This post was last modified: 07-15-2018 07:57 PM by ijabbott.)
Post: #25
RE: Casio FX991EX
(07-15-2018 05:39 PM)Albert Chan Wrote:  
(07-15-2018 04:51 PM)ijabbott Wrote:  Mine has 5 screws - 2 on the bottom edge, 2 near the middle, and 1 near the top. But yes, the case still seems to be stuck at the top after removing those screws.

EDIT: I got it apart with a bit of gentle "persuasion" with a spudger. It just seemed to have a bit of sticky junk holding one edge together!

Sorry for the mis-information, my FX-115MS had 5 screws too.

Per your advice, I "force" it open (almost breaking the thing).

Bits of Green junk is around the coin battery, voltage = 1.13 volt.

Contacts cleaned. Battery replaced, THANKS !

FYI, DollarTree store sell LR44 batteries, 4 cells for a dollar

Mine had leaked a tiny amount too. I cleaned it up with some IPA and an old toothbrush. I contemplated not replacing the battery but ended up replacing it with a spare "357" silver oxide battery. I've also cleaned a load of flux residue off the circuit board.

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07-16-2018, 12:41 AM
Post: #26
RE: Casio FX991EX
(07-15-2018 05:39 PM)Albert Chan Wrote:  FYI, DollarTree store sell LR44 batteries, 4 cells for a dollar

Don't use the cheap alkaline batteries, you are putting your far more valuable machine at risk. Also, Silver Oxide batteries (typically type 303 or 357 or SR44W, but this depends on manufacturer) last far longer and leak very rarely. They do cost more (you can find them for about $1/ea if you buy in 'bulk' of 10 or more) but the much longer life and extra safety of not damaging my toys is easily worth the extra, at least to me.

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07-16-2018, 09:33 AM (This post was last modified: 07-16-2018 09:41 AM by Tugdual.)
Post: #27
RE: Casio FX991EX
I finally opened the EX and had a quick look inside. There is already a video linked but this is my personal addition
[Image: 2075f29.jpg]

Also I measured the voltage on the solar cell and it goes well above 3V while the LR44 doesn't exceed 1.5V. Today is a sunny day and I redid the yesterday test without the LR44 and this time it passed. So a simple light bulb is not enough, you will need the real sun beam.
Ultimately I found some interesting connectors that resemble what we could see on former models of Casios that could be hacked for more features.
Look at the open circuit in betweeen P150 and P151. There are others like that. I tried to shortcut them with no effect.
[Image: 162afxh.jpg]

And trony seems to be a chinese company specialised in manufacturing solar cells http://www.trony.com/. The cell seems to be for indoor usage http://www.trony.com/pdf/2013_embedded.pdf.
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07-16-2018, 11:53 AM
Post: #28
RE: Casio FX991EX
(07-16-2018 09:33 AM)Tugdual Wrote:  I measured the voltage on the solar cell and it goes well above 3V while the LR44 doesn't exceed 1.5V. Today is a sunny day and I redid the yesterday test without the LR44 and this time it passed. So a simple light bulb is not enough, you will need the real sun beam.

What happened if the calculator is just under the desk lamp ?
Is that enough ?

It would be nice if Casio spend a bit more on the solar panel.
Not asking for much, just that it work under good light ...

I am guessing LR44 battery is the alkaline type too.
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07-16-2018, 02:58 PM
Post: #29
RE: Casio FX991EX
(07-15-2018 04:51 PM)ijabbott Wrote:  
(07-15-2018 11:51 AM)Albert Chan Wrote:  My Casio FX-115MS had a dead battery, but still work under good light.
The back is somehow stuck even with all 3 screws removed (glued stuck ?)
Cannot replace battery without breaking the calculator ...

Mine has 5 screws - 2 on the bottom edge, 2 near the middle, and 1 near the top. But yes, the case still seems to be stuck at the top after removing those screws.

EDIT: I got it apart with a bit of gentle "persuasion" with a spudger. It just seemed to have a bit of sticky junk holding one edge together! Also be aware that you need to slide the back upwards slightly to unclip it from the top edge.

At least for the EX, you only need to remove 1 screw.

My Casio fx-115ES Plus solar/battery model has six screws. One of these secures a small battery door so you can replace the battery without removing the back.
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07-16-2018, 03:54 PM
Post: #30
RE: Casio FX991EX
(07-16-2018 02:58 PM)Steve Simpkin Wrote:  My Casio fx-115ES Plus solar/battery model has six screws. One of these secures a small battery door so you can replace the battery without removing the back.

Sadly my Casio fx-115MS does not have a battery door.

Instead, after replacing the battery, I thinned out the plastic notch (with a pocket knife).
So, next time (5 years ?), changing battery will be easier.
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08-09-2018, 06:15 PM
Post: #31
RE: Casio FX991EX
Just did a search in EBay on FX991EX

If you are not careful, you might bought a knock-off by mistake.

EBay title: FX991EX 552 ClassWiz functions spreadsheet HOT
Black Color, metallic cursor key, even carbon-fiber like textual, looks like a Casio

Reading between the lines: "Casio" were never mentioned
Really check the picture: no integration, calc, dFdX ... and it is a SuperWiz :-D

What a knockoff !
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08-09-2018, 06:35 PM
Post: #32
RE: Casio FX991EX
(08-09-2018 06:15 PM)Albert Chan Wrote:  What a knockoff !

True, but note that this $3.79 (including shipping from Hong Kong!) model has these special features:

can use to calculate advanced functions
works more steadily
durable for use (as opposed, I suppose, to storage)

Also, this item is HOT. The title says so...

I'd say that anyone who buys this, and expects to receive the genuine article, probably deserves what they receive... lol

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08-09-2018, 07:33 PM
Post: #33
RE: Casio FX991EX
(08-09-2018 06:15 PM)Albert Chan Wrote:  Reading between the lines: "Casio" were never mentioned
Really check the picture: no integration, calc, dFdX ... and it is a SuperWiz :-D

What a knockoff !

Was is one of these? http://www.hpmuseum.org/forum/thread-104...l#pid94981

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08-09-2018, 08:23 PM (This post was last modified: 08-09-2018 08:24 PM by Albert Chan.)
Post: #34
RE: Casio FX991EX
hi, rprosperi:

you missed the knockoff, your $3.79 HOT calculator were a knockoff of knockoff ...
The real knockoff were named CTTTIZEN SuperWiz :-D

hi, ijabbott:

Yes, that's the one. Nice picture from your link.
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09-06-2018, 11:19 PM
Post: #35
RE: Casio FX991EX
Forget the knockoff !

Just visited a local Walmart. The real thing (Casio FX991EX) is only 11 US dollars !
Perhaps a back-to-school sale ?
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11-06-2018, 10:57 AM
Post: #36
RE: Casio FX991EX
(07-12-2018 08:28 PM)Csaba Tizedes Wrote:  Is it easy to disassembly? I think I will buy one 991ex and one 82ex and I install the 82ex dark number keypad keys into the 991ex.

Finally I bought one and OK, not so bad, but makes me crazy, I have got frequently "Not supported parameter error" when I try to draw a function with Table or Solve, eg. sin(x)/x from PI/10 to PI by PI/10 steps: link from EDU+

Any idea?!
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11-07-2018, 02:22 AM
Post: #37
RE: Casio FX991EX
Looks like everything you typed should be supported.
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11-07-2018, 12:30 PM
Post: #38
RE: Casio FX991EX
(11-07-2018 02:22 AM)Eddie W. Shore Wrote:  Looks like everything you typed should be supported.

Yes. I know from your blog, you have 991EX, can you try it? I have 991DEX version. Maybe it depends on firmware.

Thanks,
Csaba
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11-07-2018, 05:28 PM (This post was last modified: 11-07-2018 05:31 PM by klesl.)
Post: #39
RE: Casio FX991EX
Quote:Finally I bought one and OK, not so bad, but makes me crazy, I have got frequently "Not supported parameter error" when I try to draw a function with Table or Solve, eg. sin(x)/x from PI/10 to PI by PI/10 steps: link from EDU+

Any idea?!

Table and graph is OK here. I tried fx-991 EX, CE X and DE X.
http://wes.casio.com/math/index.php?q=I-...8D0A948+G-
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11-07-2018, 07:03 PM
Post: #40
RE: Casio FX991EX
(11-07-2018 05:28 PM)klesl Wrote:  
Quote:Finally I bought one and OK, not so bad, but makes me crazy, I have got frequently "Not supported parameter error" when I try to draw a function with Table or Solve, eg. sin(x)/x from PI/10 to PI by PI/10 steps: link from EDU+

Any idea?!

Table and graph is OK here. I tried fx-991 EX, CE X and DE X.
http://wes.casio.com/math/index.php?q=I-...8D0A948+G-

And both of them generates the same URL? Why my DEX's is different? As I can see, this is a simple text and the server generates the function. I will play with these hex numbers - like in the 90's when I PEEK-ed the BASIC tokens from my fx-850P memory. Good old memories Wink
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