TI-83 Plus Surgery

My job requires me to solve software problems using simple math all day long.  The calculator built into PCs would work except it's another window to keep open.  Cell phone calculators work except I would rather not put more miles than necessary on my phone by using the calculator function all the time.  I started using my old TI-82 calculator because it is in excellent shape and the larger screen allows for you to see your history of calculations, avoiding the need for the memory function.

When I was home the other day I spotted my brother's old TI-83 calculator and took it with me to use on the job.  Differences between the 82 and the 83 Plus are listed here:

https://epsstore.ti.com/OA_HTML/csksxvm.jsp?nSetId=62242

What I was most interested in, however, was the improved display.  Both have a monochrome display that is 96 X 64 pixels and 16 X 8 characters, but the TI-83 Plus has crisper black letters that are much easier to read.  There also appears to be less "depth" between the pixels of the characters and the bottom of the display, reducing the shadows that overhead lights create when viewing the characters at an angle.

Of course it was not as simple as moving my batteries from the TI-82 to the TI-83 Plus.  My brother had painted over the buttons with silver permanent marker, rendering them almost useless.  The calculator worked just fine besides that.

That's when I turned to ebay to locate a TI-83 Plus that could be used for parts.  For $12 I got a used, broken calculator with perfect buttons.  I took both calculators apart, cleaned the keys of the new one with rubbing alcohol swabs, cleaned the holes in the shell of my brother's so the keys wouldn't stick, and put humpty dumpty back together again to get myself a perfectly usable calcuator: