iFixit - Answers With Device "Casio FX-991EX"

Casio FX-991EX: Calculator is in 'PAUSE' mode

Fri, 02 Jan 2026 22:08:15 -0700

The calculation was done in VECTOR mode from the menu. When trying to do something, the calculator hangs, after clearing by the 'ON' button, you can see this status of MENU. Apart from these 3 modes, no other mode is showing, if I want to scroll up or down, the pause sign (2nd picture) is coming on the upper right side.

⁉️ How to get back all mods like before?

⟐ Commented January 02, 2026 at 22:08 MST

Casio FX-991EX: keypad does not work properly

Tue, 05 Aug 2025 03:58:29 -0700

key 2 and key 1 both work as 1
key 4 and key 5 both work as 4
key 7 and key 8 both work as 7
key STO and key ENG both work as STO
key ((-)) and key (.,") both work as ((-))
key STO and key ENG both work as ENG

⟐ Answered August 05, 2025 at 3:58 MST

Casio FX-991EX: Can I fix the calculator’s screen?

Wed, 22 Feb 2023 03:20:14 -0700

The screen has been broken for over a month now. And I really really would love to get some help on how to fix it. They said the company doesn’t sell parts of the screen but Is there like any way or anything?

Casio FX-991EX: have an issue that ENG feature is not at all working

Wed, 08 Mar 2023 01:30:13 -0700

My new scientific calculator fx991-ex have an issue that ENG feature is not at all working l have tried hard but it's not working

⟐ Answer edited March 08, 2023 at 1:30 MST

Casio FX-991EX: The arrow keys, alpha keys and the mode setup key are not working

Wed, 24 Dec 2025 04:00:37 -0700

arrow keys, alpha keys and the mode setup key are not working

Casio FX-991EX: Why is my calculator turned on and off consecutively for no reason?

Tue, 11 Mar 2025 07:04:00 -0700

can someone help? maybe it could be abattery issue but i need help :))

Casio FX-991EX: keys keep getting stuck

Sat, 27 Jul 2024 12:53:40 -0700

i attempted to take apart the calculator so i could clean the keys similarly to how you would clean laptop keys, however i was unable to separate the circuit board from the main body- is there a way to do this? The number 5 key in particular keeps getting stuck whenever i try to use it and i have tried to clean this externally but to no avail

Casio FX-991Ex: How do I fix isolated solar panel for my calculator

Sat, 07 May 2022 02:25:09 -0700

My calculator has a solar panel that is not connected to the mother board of the calculator. How do I fix or connect it so it can work with solar energy.