I did not find any bendpoints that would alter the sound. But there are some pins on the chip causing to play sounds if shorted out. This may is the keyboard matrix. It also happens that the shorting sometimes alters the timbre. To automate the switching I use a small circuit, based on a CMOS 40106 as a squarewave LFO. This LFO is triggering a CMOS 4066 analog switch. I did this four times. I now can control the speed of the automated switching and also can determine how many of the four automations are active.
There is a dial to swap crystals for the clock frequency of the chip. that alters the pitch of the sound.
