In my junkbox I found this vintage 1977 (or so) 76477 synthesizer chip- this model used to be used in arcade machines. It was gonna be another Matchbox Synth – you can see I have the case all prepped – but, whether because it’s old and broken, or because I wasn’t using it right, I couldn’t get any sounds out of it except for these.
Still, you may not have seen and heard the last of Syntho ‘77!
This is actually a really fantastic chip, and I’m jealous that you have an original. BGMicro.com sells them for about $9, and they have the data sheets too, if you’re looking for them. I bought one without knowing anything about it (I’m a sucker for anything labeled “sound generator”). A few days later, I was flipping through “Oscillator Circuits” by Rudolf F. Graf, and noticed a circuit that used the 76477 called Super Sound Generator! I built it as soon as possible, and have been making wonderful arcade-style noisy noise ever since.