Lately I've been busy restoring a Series IIx that had sustained serious damage from a leaked battery. Thanks to Peter Wielk at Horizontal Productions I was able to replace the broken cards. And after some extra debugging, the alphanumeric keyboard wasn't working, I'm able to start learning and using this dream machine.
There is a nice 8-inch floppy included with demo songs for Page 9 (Keyboard Sequencer). Here are 3 of them. Recorded from the mix output without any treatment.