Yamaha RX-N600D Owner's Manual

Use this feature to clear all the remote control codes 
previously set and reset all of them to the initial factory 
settings.

Press CODE SET using a ballpoint pen or a 
similar object.
The TRANSMIT indicator on the remote control 
flashes twice.

Press the numeric buttons to enter the code 
number “9981”.
The TRANSMIT indicator on the remote control 
flashes twice, and all the remote control codes 
previously set are cleared and reset to the initial 
factory settings.

y
If you do not press any buttons within 30 seconds after step 
2, the clearing process is canceled. In this case, repeat the 
clearing procedure.