You can use the following system exclusive messages to turn off or on parts in the MC-303. You will need to input and send these from a sequencer that allows you to create SysEx messages from scratch.
To Turn a Part Off in Sound Module Mode
Part / Message
1 / F0 41 10 00 03 12 00 40 18 08 00 20 F7
2 / F0 41 10 00 03 12 00 40 1A 08 00 1E F7
3 / F0 41 10 00 03 12 00 40 1B 08 00 1D F7
4 / F0 41 10 00 03 12 00 40 1C 08 00 1C F7
5 / F0 41 10 00 03 12 00 40 1D 08 00 1B F7
6 / F0 41 10 00 03 12 00 40 1E 08 00 1A F7
7 / F0 41 10 00 03 12 00 40 1F 08 00 19 F7
8 / F0 41 10 00 03 12 00 40 10 08 00 28 F7
9 / F0 41 10 00 03 12 00 40 11 08 00 27 F7
10 / F0 41 10 00 03 12 00 40 19 08 00 1F F7
11 / F0 41 10 00 03 12 00 40 12 08 00 26 F7
12 / F0 41 10 00 03 12 00 40 13 08 00 25 F7
13 / F0 41 10 00 03 12 00 40 14 08 00 24 F7
14 / F0 41 10 00 03 12 00 40 15 08 00 23 F7
15 / F0 41 10 00 03 12 00 40 16 08 00 22 F7
16 / F0 41 10 00 03 12 00 40 17 08 00 21 F7
To Turn a Part On in Sound Module Mode
Part / Message
1 / F0 41 10 00 03 12 00 40 18 08 01 1F F7
2 / F0 41 10 00 03 12 00 40 1A 08 01 1D F7
3 / F0 41 10 00 03 12 00 40 1B 08 01 1C F7
4 / F0 41 10 00 03 12 00 40 1C 08 01 1B F7
5 / F0 41 10 00 03 12 00 40 1D 08 01 1A F7
6 / F0 41 10 00 03 12 00 40 1E 08 01 19 F7
7 / F0 41 10 00 03 12 00 40 1F 08 01 18 F7
8 / F0 41 10 00 03 12 00 40 10 08 01 27 F7
9 / F0 41 10 00 03 12 00 40 11 08 01 26 F7
10 / F0 41 10 00 03 12 00 40 19 08 01 1E F7
11 / F0 41 10 00 03 12 00 40 12 08 01 25 F7
12 / F0 41 10 00 03 12 00 40 13 08 01 24 F7
13 / F0 41 10 00 03 12 00 40 14 08 01 23 F7
14 / F0 41 10 00 03 12 00 40 15 08 01 22 F7
15 / F0 41 10 00 03 12 00 40 16 08 01 21 F7
16 / F0 41 10 00 03 12 00 40 17 08 01 20 F7
To Turn a Part Off in Normal Mode
Part / Message
RPS PT 1 / F0 41 10 00 03 12 00 40 10 08 00 28 F7
RPS PT 2 / F0 41 10 00 03 12 00 40 11 08 00 27 F7
RPS PT 3 / F0 41 10 00 03 12 00 40 12 08 00 26 F7
RPS PT 4 / F0 41 10 00 03 12 00 40 13 08 00 25 F7
RPS PT 5 / F0 41 10 00 03 12 00 40 14 08 00 24 F7
RPS PT 6 / F0 41 10 00 03 12 00 40 15 08 00 23 F7
RPS PT 7 / F0 41 10 00 03 12 00 40 16 08 00 22 F7
RPS PT 8 / F0 41 10 00 03 12 00 40 17 08 00 21 F7
PTN PT1 / F0 41 10 00 03 12 00 40 18 08 00 20 F7
PTN PT2 / F0 41 10 00 03 12 00 40 1A 08 00 1E F7
PTN PT3 / F0 41 10 00 03 12 00 40 1B 08 00 1D F7
PTN PT4 / F0 41 10 00 03 12 00 40 1C 08 00 1C F7
PTN PT5 / F0 41 10 00 03 12 00 40 1D 08 00 1B F7
PTN PT6 / F0 41 10 00 03 12 00 40 1E 08 00 1A F7
PTN PT7 / F0 41 10 00 03 12 00 40 1F 08 00 19 F7
PTN PTR / F0 41 10 00 03 12 00 40 19 08 00 1F F7
To Turn a Part On in Normal Mode
Part / Message
RPS PT 1: F0 41 10 00 03 12 00 40 10 08 01 27 F7
RPS PT 2: F0 41 10 00 03 12 00 40 11 08 01 26 F7
RPS PT 3: F0 41 10 00 03 12 00 40 12 08 01 25 F7
RPS PT 4: F0 41 10 00 03 12 00 40 13 08 01 24 F7
RPS PT 5: F0 41 10 00 03 12 00 40 14 08 01 23 F7
RPS PT 6: F0 41 10 00 03 12 00 40 15 08 01 22 F7
RPS PT 7: F0 41 10 00 03 12 00 40 16 08 01 21 F7
RPS PT 8: F0 41 10 00 03 12 00 40 17 08 01 20 F7
PTN PT1: F0 41 10 00 03 12 00 40 18 08 01 1F F7
PTN PT2: F0 41 10 00 03 12 00 40 1A 08 01 1D F7
PTN PT3: F0 41 10 00 03 12 00 40 1B 08 01 1C F7
PTN PT4: F0 41 10 00 03 12 00 40 1C 08 01 1B F7
PTN PT5: F0 41 10 00 03 12 00 40 1D 08 01 1A F7
PTN PT6: F0 41 10 00 03 12 00 40 1E 08 01 19 F7
PTN PT7: F0 41 10 00 03 12 00 40 1F 08 01 18 F7
PTN PTR: F0 41 10 00 03 12 00 40 19 08 01 1E F7
To Turn a Part Off in Sound Module Mode
Part / Message
1 / F0 41 10 00 03 12 00 40 18 08 00 20 F7
2 / F0 41 10 00 03 12 00 40 1A 08 00 1E F7
3 / F0 41 10 00 03 12 00 40 1B 08 00 1D F7
4 / F0 41 10 00 03 12 00 40 1C 08 00 1C F7
5 / F0 41 10 00 03 12 00 40 1D 08 00 1B F7
6 / F0 41 10 00 03 12 00 40 1E 08 00 1A F7
7 / F0 41 10 00 03 12 00 40 1F 08 00 19 F7
8 / F0 41 10 00 03 12 00 40 10 08 00 28 F7
9 / F0 41 10 00 03 12 00 40 11 08 00 27 F7
10 / F0 41 10 00 03 12 00 40 19 08 00 1F F7
11 / F0 41 10 00 03 12 00 40 12 08 00 26 F7
12 / F0 41 10 00 03 12 00 40 13 08 00 25 F7
13 / F0 41 10 00 03 12 00 40 14 08 00 24 F7
14 / F0 41 10 00 03 12 00 40 15 08 00 23 F7
15 / F0 41 10 00 03 12 00 40 16 08 00 22 F7
16 / F0 41 10 00 03 12 00 40 17 08 00 21 F7
To Turn a Part On in Sound Module Mode
Part / Message
1 / F0 41 10 00 03 12 00 40 18 08 01 1F F7
2 / F0 41 10 00 03 12 00 40 1A 08 01 1D F7
3 / F0 41 10 00 03 12 00 40 1B 08 01 1C F7
4 / F0 41 10 00 03 12 00 40 1C 08 01 1B F7
5 / F0 41 10 00 03 12 00 40 1D 08 01 1A F7
6 / F0 41 10 00 03 12 00 40 1E 08 01 19 F7
7 / F0 41 10 00 03 12 00 40 1F 08 01 18 F7
8 / F0 41 10 00 03 12 00 40 10 08 01 27 F7
9 / F0 41 10 00 03 12 00 40 11 08 01 26 F7
10 / F0 41 10 00 03 12 00 40 19 08 01 1E F7
11 / F0 41 10 00 03 12 00 40 12 08 01 25 F7
12 / F0 41 10 00 03 12 00 40 13 08 01 24 F7
13 / F0 41 10 00 03 12 00 40 14 08 01 23 F7
14 / F0 41 10 00 03 12 00 40 15 08 01 22 F7
15 / F0 41 10 00 03 12 00 40 16 08 01 21 F7
16 / F0 41 10 00 03 12 00 40 17 08 01 20 F7
To Turn a Part Off in Normal Mode
Part / Message
RPS PT 1 / F0 41 10 00 03 12 00 40 10 08 00 28 F7
RPS PT 2 / F0 41 10 00 03 12 00 40 11 08 00 27 F7
RPS PT 3 / F0 41 10 00 03 12 00 40 12 08 00 26 F7
RPS PT 4 / F0 41 10 00 03 12 00 40 13 08 00 25 F7
RPS PT 5 / F0 41 10 00 03 12 00 40 14 08 00 24 F7
RPS PT 6 / F0 41 10 00 03 12 00 40 15 08 00 23 F7
RPS PT 7 / F0 41 10 00 03 12 00 40 16 08 00 22 F7
RPS PT 8 / F0 41 10 00 03 12 00 40 17 08 00 21 F7
PTN PT1 / F0 41 10 00 03 12 00 40 18 08 00 20 F7
PTN PT2 / F0 41 10 00 03 12 00 40 1A 08 00 1E F7
PTN PT3 / F0 41 10 00 03 12 00 40 1B 08 00 1D F7
PTN PT4 / F0 41 10 00 03 12 00 40 1C 08 00 1C F7
PTN PT5 / F0 41 10 00 03 12 00 40 1D 08 00 1B F7
PTN PT6 / F0 41 10 00 03 12 00 40 1E 08 00 1A F7
PTN PT7 / F0 41 10 00 03 12 00 40 1F 08 00 19 F7
PTN PTR / F0 41 10 00 03 12 00 40 19 08 00 1F F7
To Turn a Part On in Normal Mode
Part / Message
RPS PT 1: F0 41 10 00 03 12 00 40 10 08 01 27 F7
RPS PT 2: F0 41 10 00 03 12 00 40 11 08 01 26 F7
RPS PT 3: F0 41 10 00 03 12 00 40 12 08 01 25 F7
RPS PT 4: F0 41 10 00 03 12 00 40 13 08 01 24 F7
RPS PT 5: F0 41 10 00 03 12 00 40 14 08 01 23 F7
RPS PT 6: F0 41 10 00 03 12 00 40 15 08 01 22 F7
RPS PT 7: F0 41 10 00 03 12 00 40 16 08 01 21 F7
RPS PT 8: F0 41 10 00 03 12 00 40 17 08 01 20 F7
PTN PT1: F0 41 10 00 03 12 00 40 18 08 01 1F F7
PTN PT2: F0 41 10 00 03 12 00 40 1A 08 01 1D F7
PTN PT3: F0 41 10 00 03 12 00 40 1B 08 01 1C F7
PTN PT4: F0 41 10 00 03 12 00 40 1C 08 01 1B F7
PTN PT5: F0 41 10 00 03 12 00 40 1D 08 01 1A F7
PTN PT6: F0 41 10 00 03 12 00 40 1E 08 01 19 F7
PTN PT7: F0 41 10 00 03 12 00 40 1F 08 01 18 F7
PTN PTR: F0 41 10 00 03 12 00 40 19 08 01 1E F7