Super nice article! Wow. Thank you! I agree with it all. And high praise to the Internet Archive as well. <3
I got a Speak and Math together with a Speak and Spell on Ebay and bent both. Stuck with Pitch, Glitch and Loop.
For the Speak and Math I used at least 1k resistors for connections. With 20-50k resistors as limiting resistors at the Pitch/Speed potentiometer.
For the Speak and Spell only the correct Pitch points per board version (there are quite a few) works. Here I ended up using a 1M ohm potentiometer as a Voltage divider / pitch knob.
