Cleaning and trying out a Casio FX-850P pocket computer

In whch yr hmbl svt tears down and... tears up?... a classic BASIC-running pocket computer, and then writes a tiny game for it.

00:01:48 Begin teardown
00:18:15 Reassembly
00:48:04 Demonstration
01:15:07 Conclusion

 The FX-850P is one of the archetypal BASIC pocket computers, from 1987. It's got 8kB of RAM, a mysterious and undocumented 1.2MHz processor, a two-line LCD that's surprisingly readable, and an ortho keyboard from before they were cool. It's a calculator, but it's also a fully programmable and surprisingly powerful fully fledged computer running a dialect of BASIC with a 100+ hour battery life. Ideal for the 1980s computer user who can't bear to be separated from their machine at any time.

Here I tear one down for cleaning, successfully reassemble it, and then demonstrate its various features. Also, I struggle with camera focus...