Most common remote codes for RCA Home Theater:
Audio = 1254, 2154, 1913
Video = 1022, 1060, 1132
Please try the following remote codes with the unit turned ON to test if the unit will power OFF.
5 digit remote codes for RCA home theaters: 64257, 31254, 18192, 51472, 18704, 51216, 18448, 19216, 51728, 18960
Test the RCA Home Theater in Audio mode using 1254 as the setup code. Press Setup once and enter the 51988 code. The remote will send the IR signal. Holding the 5th digit will cause the signal to repeat and this should turn the volume down.