hercules dj console mk2 jog wheel broken

good day everyone

i have a herculer dj console mk 2
the consoles right side jog wheel is broken.
being an electronic tech i would like to repair the console myself.
i have open the console and found the wheel have slots and an ir led and photo transistor is "counting" slots in the wheel.

i have measured the led and transistor and its seems to be ok
i would like to trace the pulses from the photo transister through the rest of the circuitry.
would anyone happen to have a circuit diagram this  console.
it would make the repair much easier

thanks in advance