Maybe the Oveurture is option programmed to ignore remote control commands (option 0).
Beo4s do not really "marry" to equipment so the fact that it was used to control an Avant TV doesn't matter.
Try this with your Beo4:
- Press and hold the power button (red dot)
- press "list" until it displays [OPTION?]
- let go of both buttons
- press "Go" until it displays [A.OPT]
- press 1
This should put the Oveurture into "Option 1" programming which is what it should have (assuming it is a stand-alone system with no Beo TV in the same room and not master linked to other Beo equipment).
Then again, it might be option 2... according to the ML handbook, it should be 2, but the BS4000 manual says 1 is the factory setting. Maybe both work...
Stan