Casio PX-720 Service Manual & Parts Manual page 21

3. ROM version check (Internal / External)
 Press "TONE/SETTING" button to perform the "ROM check (Internal)."
The confirmation chords C4, E4, G4 sounds.
 Each time "▲/" button is pressed, the different LEDs light.
Confirm with the lit LED.
 Press "TONE/SETTING" button to perform the "ROM check (External)."
The confirmation chords C4, E4, G4 sounds.
 Each time "▲/" button is pressed, the different LEDs light.
Confirm with the lit LED.
LED Status >
0 : "/" LED
2 : "CLASSIC" LED
4 : "R" LED
6 : "L + MODERN" LED
8 : "L + RECORDER" LED
Internal ROM (07061813550):
External ROM (07061813550):
Internal ROM LED Sequence
1:(0) "/" LED
2: (7) "L + CLASSIC" LED
3: (0) " "/" LED
4: (6) "L + MODERN" LED
5: (1) "MODERN" LED
6: (8) "L + RECORDER" LED
7: (1) "MODERN" LED
8: (3) "RECORDER" LED
9: (5) "L" LED
10: (5) "L" LED
4. BUTTON check
 Press "TONE/SETTING" button to perform the "BUTTON check."
The confirmation chords C4, E4, G4 sounds.
 Press the buttons in the order indicated in the illustration on the right.
Each time the button is pressed, the confirmation chord C6 sounds.
When "MODERN" button is pressed finally, the confirmation chords C4, E4, G4 sound.
1 : "MODERN" LED
3 : "RECORDER" LED
5 : "L" LED
7 : "L + CLASSIC" LED
9 : "L + R" LED
0→7→0→6→1→8→1→3→5→5
0→7→0→6→1→8→1→3→5→5
External ROM LED Sequence
1: (0) "/" LED
2: (7) "L + CLASSIC" LED
3: (0) " "/" LED
4: (6) "L + MODERN" LED
5: (1) "MODERN" LED
6: (8) "L + RECORDER" LED
7: (1) "MODERN" LED
8: (3) "RECORDER" LED
9: (5) "L" LED
10: (5) "L" LED
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