There is a better glitch randomization than the one in the schematic, and that is to manipulate with the crystal directly. My object was a SA-21 which have the same circuits. I did not do the "pitch shift" as I didn't have another crystal, but I could confuse the cpu in wonderful ways by interrupting the clock pulses from the crystal, by brief shortcircuiting of the crystals legs to nearby components. It's worth experimenting with. 

Also, I cound not get the power crash to work on the SA-21, even with a 500 ohm pot and without the speakers. But the feedback loop and the 5ths mod is great.