This is 3 pictures of the PCB of a VL-Tone VL-1 patched together to one. After a shoutout on twitter people were taking apart their VL-1s for me and took pictures, what a great thing! The main connections for the switch are on the bottom.

The PT-10 that I own has the same chip in the same case, so I wanted to see if I can add something to the keyboard, that wasn't there before. Wait, did I hack something?

Counting from the bottom left, pin 8, 9 and 10 are the octave switches, connected through a diode and a 3 way switch to the very last pin. You (sadly) have to cut where the unicorn is pointing to, but it's reversible if you really need to do that. 

Next up should be tracing the ADSR switch, to get a new instrument out of it. At one point I need to see if I can connect an LED display to replace the LCD.