The indicator light will flash twice to confirm the remote has been completely reset to factory defaults.
Tuner Controls
If you’ve lost the code list, let the remote brute-force search. onkyo rc-799m remote manual
If the remote stops responding, try the following:
Press the button once more. The light will flash twice to confirm the remote has been reset to factory defaults. The indicator light will flash twice to confirm
The RC-799M is an infrared (IR) remote control that operates on two AA batteries. It features a logical, zone-based layout designed to manage both basic receiver functions and advanced multi-zone audio setups. Key Control Zones
Press and hold the device button at the top of the remote. onkyo rc-799m remote manual
Turns the main Onkyo AV receiver on or puts it into standby mode.