John, you mean on its side? If so, there may be three caveats:

1) The designed-in natural heat convection may not allow for continuous high-level playing.

2) The magnetic field from the power transformer in the receiver may distort the TV's color.

3) The TV may induce hum and/or other noises in the audio circuitry of the receiver.

Larry
www.fineelectricco.com