Technics SX PR603 Digital Piano Speaker Hiss

[cpkoch]

When I use the head-phones there is no sign of what I'll cal "hissing".  So I replaced the speakers thinking they were on their last legs. There remains the hissing but to my ear, somewhat less.  My question ... if no hiss is apparent using head phones can the problem still be within the PC Board that creates the sound?  or within the Power Supply?    Your help  is appreciated.

[pianotuner steveo]

Is your keyboard not working at all or are you only complaining about background noise?

I'm not sure if anyone on this forum knows much about digital piano service. I briefly attempted to service them about 20 years ago but quickly found out they were too much like computers, and far more complicated than pianos and electric pianos.

If you are not that familiar with electronics, you would be better off taking it to an expert.

It could be power supply issues, output amp issues, or elsewhere.

Was the keyboard ever dropped or did liquid spill on it?

[cpkoch]

Just the background noise.  The piano work great otherwise! 

[pianotuner steveo]

Has it always had the hiss?

It may be normal....

[cpkoch]

Not at all normal.  Started about a n=month ago!

[doctor]

I service digital devices (synthesizers, pianos, effects, etc.) during more than 20 years and I absolutely agree with pianotuner steveo. Any electronic  problem should be only fixed by professional. It is my opinion also applies to analog devices.