Don't use the Receiver mode option in the menu for the third receiver, go to Advanced setup, there you can chose from 8 IR codesets, from 00001 to 00008. Since the other two are using 00001 & 00002, you have to pick between 00003 to 00008 for third receiver. just remember to cover the other receiver while you changing codesets.


see thread:


[Link: dbstalk.com]