Yamaha PSR 2100 distortion sound

by Stephen
(India )

When I switch on the Yamaha PSR 2100,I get a disturbing highly flickering sound.

The noise goes of when I turn off the DSP switch.
When I switch on the DSP and play keyboard the noise is high.

When I leave the keyboard switched on for 10 mins everything gets to normal and keyboard is working fine without any noise.

Seems that when the keyboard gets heated up it comes to normal.

Can anyone help this. I guess some thing about bad capacitor.when they heat up the keyboard starts working as normal.