This is a Texas Instruments TI-1200 electronic calculator I bought at a local thrift store. It was first released in 1975, and was discontinued sometime in 1977. My version is the last model before it was discontinued, so I think it is possibly kind of rare. It also still powers on!

This basic calculator features an 8 digit “Bubble” LED display. It also uses a standard nine volt battery.

To start dissasembly of your calculator, you will need a Philips Screwdriver.

Remove all four screws from the case of the calculator in order to open the case.

Once all four screws are removed, you can lift the top part of the case off.

Inside the case of the calculator, there is a green PCB, LED display, and a keypad. There is also a small microcontroller. In this case, the chip is a TMS-0972 Calculator-On-A-Chip.

I found the LED display to be quite interesting, since the silicon bond wires are visible underneath the clear plastic cover. If power is applied, it can still light up!