Try these:

With the player connected up to your home amp, turn the volume up on the amp - do you get any 'electronic noise'?

Double check that the unit is playing - time is counting up, visuals are moving etc. Also check the EQ settings.

Try plugging one RCA in and touch the shield of the other one to the player case.

Check that there are no icons on the screen that shouldn't be there - is the player thinging it is on phone mute?