I have a dish 500 with a dish pro digital LNBF. I have 3 receivers 1, HD receiver and 2 DishDVRs. Everything works fine on the HD receiver but I cannot get local channels on the 2 DVRs. The error code screen is 002 indicating something is blocking the signal or bad weather, neither are the case. It's been this way for 2 months. Is this an LNB problem? Should I replace it?