TI-84+ SE Backlight

Finally you can do math in the dark.

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This is an EL backlight to my TI-84. Some people have done this before, but they were always clumsy solutions involving plexiglass sheets and LEDs. EL backlights were always to big and clunky to fit inside the calculator... until now! Adafruit is selling thin EL panels and tiny inverters. Total cost: $32.84

​The backlight is an electroluminescent panel which glows a nice cool blue color. Unfortunately when its off its kind of an ugly pinkish color, but why would you ever turn it off?

Its controlled by a button on the left side of the calculator and powered by the calculator's own AA batteries.

The inverter is the tiniest one Adafruit sells. Its so tiny, it can't even power the whole EL panel until you cut it down to the size of the screen. Don't try to test your panel until you cut it down to size.

A new polarizer is optional, but recommended for this project. You can buy new polarizing filters on ​Amazon or your favorite science shop.

Don't do this project right before finals or anything important (unless you have a spare calculator). It is an extremely invasive procedure and theres a high risk of bricking your calculator.

This should also work on any TI-8X calculator except the TI-89. The 89 has two ribbon cables going to the LCD instead of just one. The arrangement makes it impossible to remove the LCD without desoldering at least one ribbon cable. Good luck with that.

  • Tyler Anderson01/29/2014 at 02:01 0 comments

    Remember to archive any programs and variables you want to save. The RAM is going to get cleared.

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  • 1
    Step 1

    Take off the faceplate, remove all the batteries (especially the backup coin cell), unscrew the case, and pry it open. You're going to need a torx screwdriver for the case screws. Theres also clips holding the case together. Don't be too worried if you screw them up because they're redundant.

  • 2
    Step 2

    Unscrew the circuit board and pull off the RF shield. Be carefull because once you take the board out there will be nothing holding the buttons in.

  • 3
    Step 3

    As you can see in the picture, the screen is glued onto the PCB with a thick piece of aluminium between them. Now we have to remove the LCD screen and plate from the motherboard. This is tricky. You must be extremely careful, because the LCD is made from very fragile glass. It will chip or crack very easily. Also be careful not to cut or dislodge the ribbon cable. If either the screen or ribbon cable is broken, it cannot be fixed. There is no hope. You're calculator is dead. The end.

    Begin by using a knife to pry the aluminium plate off of the motherboard. Be patient and take your time.

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voxadam wrote 02/28/2014 at 11:03 point
Great project. Maybe I'll try something similar with real calculator (e.g. HP 48G/GX or 50G)

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GuyisIT wrote 02/18/2014 at 21:33 point
How much does the backlight affect battery life? Otherwise, this is a pretty awesome hack!

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