The Yamaha RX-17 drum machine was the low-cost variation of the professional Yamaha RX- drum machine series and doesn't offer a notably large range of functions. So, it's cheap to get nowadays and, when modified, a fascinating musical instrument.
This drum machine's sound is typical for the eighties, with natural drum set samples. The partly open chip architecture allows a bit of manipulation, enabling some interesting effects. I built an 8-switch matrix into the sample ROM area, resulting in beautiful noice and vocoder-like effects.