TI-83 Teardown (Part 1 of ??)

Hey all!

Ordered a few dud TI calculators, a TI-83 Plus and two TI-86s, on Ebay a while back and finally have a use for them: their LCDs. I began to disassemble the TI-83 Plus to get to the LCD and took a few pictures of the process. Once I have the LCD, I've found another project that managed to get one working, but he's a lot more hardcore than I am so I'll be using an Arduino Mega to (hopefully) control it.

Part 1: Removing the LCD

The front of the TI-83 The front of the 83 looks nice, no scratches or anything. Too bad it'll never be functional again!

On the back of the 83 there were a few Torx-T6 screws that were fairly easy to get off, and a Phillips screw in the battery compartment (be sure to remove the backup battery!)

The battery compartment

After that there was a series of clips, one on the top, above the screen, and two on the lower areas of the sides that need to be un-clipped (prying carefully with a thin, flat object seemed to do the trick). They look like this:

The clips on the interior of the body

Once the case is off, you are presented with the interior! ...After you remove the board shielding. There're two Phillips screws down near the bottom. After that, there's a bit of adhesive under it that peels off fairly easy.

The board shielding

Once the shield's off, there are a few chips that stand out on the board at first glance:

  • Inventec 6SI837, which, as far as I can tell, is an in-house 6MHz Z-80 processor
  • Fujitsu MBM29LV400TC 512KB Flash memory
  • 2x Fairchild MBM29LV400TC voltage interface transceivers

At the top, the display is mounted onto a daughter board, which is controlled by the main board via a ribbon cable. On the bottom sides, there are 2 more Phillips screws which hold down the daughter board. I removed these and, being unable to mount the irregular ribbon cable to an Adafruit Multi-pitch FPC Adapter, removed the cable entirely and carefully scratched the adhesive off the copper pads on the daughter board. I found an old IDE connector cable and cut it down to be a 2x9 connector (the one on the left) to fit the board's 17 pins.

The new connector

I spliced the cable and stripped the ends to prepare for the solder nightmare:

The new cable next to the daughter board

The solder job done

The solder job took about a half-hour and I coated the connections in glue (Elmers, didn't have epoxy on-hand, unfortunately) to try and decrease the chance i'll rip them off when I move the cable.

The great gooey glue glob

Next comes the fun part: programming!


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