For R15 Tuner # 2, relating to DirecTV DVRs and receivers. I bought two R15 DVR over the weekend but I can not get tuner 2 to work on both receivers. I have swap antenna cables between the #1 and #2 tuners but still can not get any signal on tuner #2... but when connected on tuner #1 i get good signal.. is there a special setting i need to enable to turn on tuner #2? i hate to think both rcvr are defective. tia..