Recently, I’ve gotten into the business of buying bulk orders of TI graphing calcs on Ebay listed for parts of repair, mostly because I’ve started getting into the collection and documentation of old hardware revisions. I’ve found that, in most cases, screen issues caused by both ribbon cables can be fixed by nothing more than a soldering iron. For the 17-contact ribbon cable, I set my soldering iron to the lowest temperature (150C) and press firmly on the glue on each of the contacts in 2-3 places per contact using the tip of the soldering iron for about 2 seconds. For the LCD cable, I press firmly on the ribbon cable contact strip with the iron while slowly dragging the iron across the cable (with the plastic sheath still on the cable). Though this isn’t the best way to do it, it has succeeded in fixing every TI-83 I have attempted to fix, except in a couple cases where the ribbon cable was partially severed and I had to solder my own connections. I measure the resistance of the connections before I put the calc together, and redo connections with resistances above about 8 Ohms.

The 83+ and earlier calcs are significantly easier to work on than the 84 and later. On some calcs, like my 84 Pocket SE, dead lines may be caused by connections between the LCD panel and ribbon cable that are inaccessible because they are physically beneath the LCD. I have yet to figure out how to fix calcs with this issue, as I do not know how to separate the LCD from the PCB beneath it without breaking the fragile glass.

I am not sure if anyone has ever tried that, but I want to see if a failed fine ribbon cable can be replaced with fine enameled wires that were pre-arranged such that they rigidly remain correctly spaced apart. For example, by placing them on adhesive tape, hot glue or the like. This could allow them to be soldered somewhat similarly to a regular SMD package with small pin pitch.

If anyone has a calculator with a failed fine ribbon cable and is willing to ship it to Germany, I would really like to try this - but as a word of caution, I cannot guarantee that whatever I do will not destroy the calculator.