Hi,

My TI-83+ (from 1999) has issues with its display. Pictures here: http://imgur.com/a/XP6Ti

- The display output appears scrambled. Pressing "2nd + quit" fixes the display (reliably). Attached picture with the scrambled output and after pressing "2nd + quit".
- All menus e.g. stat, list, test, vars, distr, etc. appear scrambled and are unuseable - obviously "2nd + quit" gets me back to the normal calculator mode
- The LCD displays a black, almost solid, rectangle. You can see it the output on the screen if you look from an angle. "2nd + quit" does not work; but cycling "2nd + down", "2nd + up" eventually fixes it. The LCD appears to be pulsing when this issue appears. Turning on/off fixes it at times. This issue does not appear all the time, but when it appears, it appears that it's more likely it will also appear next time I start the calculator.

The same issues appear roughly half a year ago but then magically disappeared again.

Googling suggests that this may be a ribbon cable failure and can possibly be repaired with some soldering. I've never soldered anything in my life, so here are my questions:

- Is this indeed likely to be a ribbon cable failure?
- Cheapest way of fixing this? I have a fairly steady hand, and have taken the calculator apart in the past to clean the keyboard (hence the "log" in the picture is the wrong way round).

Thanks. Really appreciate any comments![/list]

Yep; that's a textbook ribbon cable failure. The cheapest way is to solder new wires across the failed portions of the ribbon cable; the most reliable way is to remove the ribbon cable and solder new wires across all 16ish connections. See this thread for more information.

Thank you! I've read the thread and roughly understand what is involved. Never having soldered before, it sounds a little daring, obviously. Do you think the following tools would do the job? (Yes, I am a cheap grad student, and these were exclusively selected by price.)

https://www.radioshack.com/products/5-piece-basic-soldering-set?variant=5717865349
http://www.microcenter.com/product/237694/Mini_3_1-2_Digit_19_Range_Digital_Multimeter (Multimeter)
http://www.microcenter.com/product/426735/Solder_Tool_Kit_(SR-1,_SP-4,_SW-3,_LF-99)

Thanks!

A multimeter, 25-60 watt soldering iron with a reasonably fine tip, solder, flux, 28 to 30 gauge wire, and two screwdrivers (Phillips #0, Torx T6) is all you should need to do the repair. As far as the soldering iron goes, a soldering station makes life a lot easier.

*thwacks the experienced KermMartian with more suggestions for ian*