Korg pa 300 professional arranger keyboard

I am new here. By sharing information, I hope I can get assistance regarding my KROG PA300 Keyboard having NO sound at all with keys and also on demo songs played back. I checked all settings seems ok, did reset, still no sound. Connected jack output through a amp, heard on beep beep noise.
Please good people, I need help in sharing any experience, getting spare parts and its service manual.

Thank you