Apple III buzzing noise

[matacao]

Hi,

This afternoon, I have decided to restart my Apple ///, after some effort it works but the speaker make continuously a buzzing noise. Have you any idea of what could cause this ?

Thanks, matacao.

Video with the noisy sound:

http://i1165.photobucket.com/albums/q583/matacao/th_Apple%20III%20Buzzing%20Noise.mp4

 

[CelGen]

Stuck key possibly?

 

[matacao]

I have tested all keys and there is no problem, I think that I have an oscillation due to a faulty component in the sound circuit.