Sony STR-K1900P

[peshop]

Hi,
My Sony STR-K1900P receiver started having sound distortion on all the speakers, no matter what source I use - TV or radio.
Here is the schema of the main board, any suggestions?

Thanks

 

[peshop]

Following post on a similar problem I checked the resistors connected to the emitters and bases of the driving transistors Q703, Q704, Q654, Q653, Q604, Q604, Q754, Q753, Q503 & Q504 but all of them have values according to the specifications.

 

[newenglandj]

Is the distortion equally present at all volumes? Given that the distortion occurs regardless of source or speaker output, I'd start checking voltages against what's stated in the service manual.

 

[peshop]

Is the distortion equally present at all volumes? Given that the distortion occurs regardless of source or speaker output, I'd start checking voltages against what's stated in the service manual.

Yes, all the channels are distorted.
Thank you for the advice, do you mean the voltages on the driver transistors or the supply ones?

 

[newenglandj]

Supply rail voltage, but it would be a good idea to check everything along the way against what's stated on the schematic.