The Jupiter-50 has a separate MIDI channel setting for each of the 3 internal parts (PERC / LOWER, UPPER, and SOLO). The default settings are:
PERC / LOWER = MIDI Channel 4
UPPER = MIDI Channel 1
SOLO = MIDI Channel 3
You can change these using the following procedure:
1. Press MENU.
2. Press F3 (SYSTEM).
3. Press F1 (SETUP).
4. Press F4 (MIDI).
5. Use the ^ / v Arrow buttons to select "UPPER Part Channel," "SOLO Part Channel," or "PERC / LOWER Part Channel" and use the Value Dial to select the desired MIDI channel for each part.
6. To save your settings, press WRITE, then press F5 (OK) to confirm.
7. Press EXIT twice to return to the main screen.