Just taking a wild stab at this, while not knowing the equipment: How do the extra receivers connect? Do they plug into a jack on the box? Might such a plug disconnect the IR sensor inside the box, like a headphone plug/jack turns off speakers?
This sounds unlikely, but maybe it might stimulate some thinking.
A good answer is easier with a clear question giving the make and model of everything. "The biggest problem in communication is the illusion that it has taken place." -- G. “Bernie” Shaw
