<![CDATA[iFixit - Answers With Device "Casio FX-991ES Plus"]]> https://www.ifixit.com/Answers/Device/Casio_FX-991ES_Plus?rss=yes en-US Sat, 04 Apr 2026 21:11:20 -0700 <![CDATA[Casio FX-991ES Plus: Not working. No display. Better also changed. what should I do?]]> My Casio fx991 es plus calc not working what should I do? No display battery also changed. Advise me please.

⟐ Answered March 23, 2026 at 3:47 MST

]]> https://www.ifixit.com/Answers/View/426966/Not+working.+No+display.+Better+also+changed.+what+should+I+do https://www.ifixit.com/Answers/View/426966 Mon, 23 Mar 2026 03:47:59 -0700 <![CDATA[Casio FX-991ES Plus: How to repair the display]]> How to repair the display of a Casio FX-991ES Plus Calculator

⟐ Commented April 08, 2025 at 23:29 MST

]]> https://www.ifixit.com/Answers/View/499787/How+to+repair+the+display https://www.ifixit.com/Answers/View/499787 Tue, 08 Apr 2025 23:29:40 -0700 <![CDATA[casio fx-991es plus: LCD has blotch after I dropped my calculator. Can this be fixed?]]> I dropped my calculator the other night and some faint cracks and a blue blotch runs vertical across the lcd. It still works but the numbers where the blue blotch is can't be seen. Can I fix this somehow? Or is it possible to have the lcd replaced?

⟐ Commented December 16, 2022 at 4:22 MST

]]> https://www.ifixit.com/Answers/View/327894/LCD+has+blotch+after+I+dropped+my+calculator.+Can+this+be+fixed https://www.ifixit.com/Answers/View/327894 Fri, 16 Dec 2022 04:22:43 -0700 <![CDATA[Casio FX-991ES Plus: How do I fix my calculator that only runs on solar power?]]> My Casio fx-991ES PLUS was dropped and now the display does not light up unless it is under a light source. It has a mini solar panel which I assume it using for power and it has new batteries in it but they do not seem to work. Is there something I can do to fix it?

⟐ Commented March 23, 2024 at 18:15 MST

]]> https://www.ifixit.com/Answers/View/597603/How+do+I+fix+my+calculator+that+only+runs+on+solar+power https://www.ifixit.com/Answers/View/597603 Sat, 23 Mar 2024 18:15:54 -0700 <![CDATA[Casio FX-991ES Plus: Facing Problem on my calculator]]> My calculator is fully reversed. The number is reversed. Everything is rotated into 90 degree. How can i fix this problem?

⟐ Answered June 01, 2025 at 23:52 MST

]]> https://www.ifixit.com/Answers/View/529440/Facing+Problem+on+my+calculator https://www.ifixit.com/Answers/View/529440 Sun, 01 Jun 2025 23:52:08 -0700 <![CDATA[Casio FX-991ES Plus: How to fix calculator suddenly goes off after calculation]]> As soon as I type any question and then press equal to it will give me the answer but it will suddenly go off in 5 seconds

⟐ Commented September 14, 2025 at 5:15 MST

]]> https://www.ifixit.com/Answers/View/466260/How+to+fix+calculator+suddenly+goes+off+after+calculation https://www.ifixit.com/Answers/View/466260 Sun, 14 Sep 2025 05:15:30 -0700 <![CDATA[Casio FX-991ES Plus: need help to repair my calculator]]> i guess water fell on my calculator. now its not working. i have to use my calculator in my papers which are starting from monday what shoukd i do?

⟐ Answered March 20, 2021 at 8:50 MST

]]> https://www.ifixit.com/Answers/View/533885/need+help+to+repair+my+calculator https://www.ifixit.com/Answers/View/533885 Sat, 20 Mar 2021 08:50:37 -0700 <![CDATA[Casio FX-991ES Plus: Solar panel is broken]]>

Unfortunately I dropped my calculator and my solar was broken How I will fixed that Solar panel ?

⟐ Answered March 31, 2021 at 7:31 MST

]]> https://www.ifixit.com/Answers/View/686627/Solar+panel+is+broken https://www.ifixit.com/Answers/View/686627 Wed, 31 Mar 2021 07:31:12 -0700 <![CDATA[Casio FX-991ES Plus: My Casio power button is not working]]> All buttons work except the power button. If you ask me how do I know, I tried connecting the calculator to the power supply and my system worked.

⟐ Answered August 18, 2023 at 19:35 MST

]]> https://www.ifixit.com/Answers/View/792012/My+Casio+power+button+is+not+working https://www.ifixit.com/Answers/View/792012 Fri, 18 Aug 2023 19:35:59 -0700 <![CDATA[Casio FX-991ES Plus: Why doesn't my calculator turn on though I just got it?]]> My calculator is new and has no faults i hav tried putting my calculator under my laptop and outside but it is not turning on so what should i do.

⟐ Answered May 07, 2023 at 9:33 MST

]]> https://www.ifixit.com/Answers/View/791025/Why+doesn't+my+calculator+turn+on+though+I+just+got+it https://www.ifixit.com/Answers/View/791025 Sun, 07 May 2023 09:33:08 -0700 <![CDATA[Casio FX-991ES Plus: Can't find the brightness changer mode]]> I have Casio 991-MS calculator and have an issue to change my display brightness,when I switching with Mode key,I can't find Cont mode,while in another same calculator there is , anybody can help me with that quickly?

⟐ Answered December 26, 2022 at 1:35 MST

]]> https://www.ifixit.com/Answers/View/761128/Can't+find+the+brightness+changer+mode https://www.ifixit.com/Answers/View/761128 Mon, 26 Dec 2022 01:35:21 -0700 <![CDATA[Casio FX-991ES Plus: Why it is hang after pressing √(10) *10^13]]> How to unhang calculator

⟐ Commented April 21, 2022 at 3:22 MST

]]> https://www.ifixit.com/Answers/View/729943/Why+it+is+hang+after+pressing+%E2%88%9A(10)+*10%5E13 https://www.ifixit.com/Answers/View/729943 Thu, 21 Apr 2022 03:22:03 -0700 <![CDATA[Casio FX-991ES Plus: My calculator is not turning on]]> My calculator is not turning on

⟐ Answered September 08, 2021 at 1:35 MST

]]> https://www.ifixit.com/Answers/View/704909/My+calculator+is+not+turning+on https://www.ifixit.com/Answers/View/704909 Wed, 08 Sep 2021 01:35:53 -0700 <![CDATA[Casio FX-991ES Plus: How to Change Mode]]> My answers are all giving in fractions

How do I change it to decimal?

It's in maths mode

How can I change the mode?

⟐ Answered February 16, 2021 at 20:27 MST

]]> https://www.ifixit.com/Answers/View/680960/How+to+Change+Mode https://www.ifixit.com/Answers/View/680960 Tue, 16 Feb 2021 20:27:33 -0700 <![CDATA[Casio FX-991ES Plus: Where I get service parts]]> My display got damaged.i need to replace this display with a working one.where i get the orginal spares of casio?

⟐ Answer accepted February 15, 2021 at 7:32 MST

]]> https://www.ifixit.com/Answers/View/680761/Where+I+get+service+parts https://www.ifixit.com/Answers/View/680761 Mon, 15 Feb 2021 07:32:50 -0700 <![CDATA[Casio FX-991ES Plus: Replacing LCD Screen that got cracked]]> So I have two FX991ES’es (One is actually a better version, they look the same, same shell, same everything just different functions one is a slightly better version (115ES PLUS) still there the same basicly.

So my 115ES display is broken and I would like to try to fix it before throwing it away and buying a new one, I have the 991ES display which from opening I see they have the same ribbon and everything. I don’t care about breaking anything as I’m throwing it away anyways and I don’t have any expierence with stuff like this.

How would one go in disconnecting a ribbon from the board and reconnecting it? Does anyone have an idea how the mechanism locking it in functions? I would guess it’s some kind of glue or adheseve, but I’m just shooting in the dark here.

Thank’s.


TL;DR

I have two screens I want to replace my FX115ES PLUS Screen with my FX991ES Plus screen, but confused about how to disconnect/reconnect the ribbon cables.

⟐ Commented September 13, 2020 at 22:07 MST

]]> https://www.ifixit.com/Answers/View/529303/Replacing+LCD+Screen+that+got+cracked https://www.ifixit.com/Answers/View/529303 Sun, 13 Sep 2020 22:07:35 -0700 <![CDATA[Casio FX-991ES Plus: How to remove stripes on my calculator.]]> I have stripes on my calculator and so am not able to see some inputs.

⟐ Answered June 07, 2020 at 1:58 MST

]]> https://www.ifixit.com/Answers/View/639302/How+to+remove+stripes+on+my+calculator. https://www.ifixit.com/Answers/View/639302 Sun, 07 Jun 2020 01:58:24 -0700 <![CDATA[Casio FX-991ES Plus: Ratio won’t go into decimal]]> Unless I have a perfect ratio my ratio would go into a decimal

⟐ Answered August 12, 2019 at 9:26 MST

]]> https://www.ifixit.com/Answers/View/564718/Ratio+won%E2%80%99t+go+into+decimal https://www.ifixit.com/Answers/View/564718 Mon, 12 Aug 2019 09:26:39 -0700 <![CDATA[Casio FX-991ES Plus: in dark place cannot see display]]> 991es plus i bought 13years ago, now i use it to change the battery but lighting strong place there can use it. no lighting dark place cannot see the display but its working. how should i do?

]]> https://www.ifixit.com/Answers/View/906796/in+dark+place+cannot+see+display https://www.ifixit.com/Answers/View/906796 Wed, 09 Jul 2025 22:29:03 -0700 <![CDATA[Casio FX-991ES Plus: Facing Problem on my calculator]]> Block Image

⟐ Edited June 02, 2025 at 1:05 MST

]]> https://www.ifixit.com/Answers/View/902251/Facing+Problem+on+my+calculator https://www.ifixit.com/Answers/View/902251 Mon, 02 Jun 2025 01:05:08 -0700