Hi I recently bought a second hand Onkyo HT-R390 which came with a remote (RC-762M).

I can’t get the remote to work on all the functions. It does work for many of the functions which makes me think I’m possibly not using it correctly. The remote is paired on channel 3. Many of the buttons don’t trigger the red light (on the remote) when depressed and none of the buttons that don’t activate the red light work which suggests the remote is faulty.  

Buttons that don’t activate the red light: On/standby, any of the input selector buttons, muting, disk/album, volume, or any of the listening mode buttons.

Is it time for me to get a new remote or am I missing something?

Thanks in advance for your help