Casio ap-21 - No Sound Troubleshooting; Distorted Sound Troubleshooting

— 12 —
2. No sound
Does the power indicator
light up?
Check the main volume.
Is it OK?
Does the demo tune sound?
Replace keyboard PCBs.
Disconnect CA
connectors on the main PCB.
Follow "No power"
troubleshooting.
No
Yes
Yes
Yes
No
No
Replace main volume.
Press Demo button.
Replace the main PCB.
Replace PS2M PCB.
Is a sound ok?
Yes
No
Replace MA1M PCB.
End
3. Distorted sound