I have had a dish 500 for several years with one receiver. We wanted to expand to 3 receivers. I have 4 separate cables run from the dish for future use. I purchased a 508 and a 510 receiver and a dish pro quad LNB. The two new DVR receivers work fine but my old receiver doesn't have a signal, or it only gets the odd transponders on satellite 110. I am pretty sure it's not the cable because I have tried both cables that I am not using and get the same result. Can anyone tell me what my problem is?