Yamaha Cvp503 piano. keyboard and buttons unresponsive

by Iordanis Sav
(Greece)

After the boot screen and the 1st click sound, the piano does not produce sounds and the rubber buttons don't do anything. Only the display is on. If i press the last key at boot time, it performs initialization, but then it is still unresponsive as described. Also, if i press the C#2 major to start the test screen, the display halts showing the word "Test" and nothing else. Is any pcb the fault? The ROM? Firmware? I did a firmware upgrade some years ago succesfully. I am completely stuck.

A fellow electronics technitian, checked the boards and said it is probably the EIF circuit board, but he was not absolutely sure. Where can i order it from? I haven't found and luck looking online. Any suggestions?

iordanissav@ in.gr