So my PX-575R had the exact problem described above in the first post. Fixed it by doing the following:
With power on hold down the Transpose/Function button and the 1 button for about 10-15 seconds (middle of unit under Registration heading, there are buttons 1, 2, 3, and 4). There is crackling/static noises that come from the speakers so make sure the volume nob is no more than a quarter rotated. Release the buttons. Do the same using the other numbered buttons, namely hold down the Transpose button and the 2 button for 10-15 seconds (more static sounds from speakers) then release, again with Transpose and 3, again with Transpose and 4.
After doing this the Transpose button should now respond when simply pressed in a normal manner (not held down). Assuming the Transpose button on your device now responds normally, do the following procedure:
Press and release Transpose, press down arrow three times, press right arrow two times, press + (yes) button two times. Unit should now reset to factory, but still no sound. Power off unit and wait 10 seconds, power on unit as normal. Unit now functions properly.
