Hi Mike,
If you connect an external Amplifier to the Line Out sockets, can you hear the sound?
If you can, then it looks like the Power Amplifier module in your KN7000 has given up the ghost!

Also, the 'Bump' which your Granddaughter reported, would suggest that something failed.
_________________________
Willum

After silence, that which comes nearest to expressing the inexpressible is Music.
Aldous Huxley
( especially when the music is played on a KN7000....)