i would take the box to a friends home that has a satellite dish on their roof/ home ect" and get them to test the box there, because it could just be the LNB thats on the blink at your home , the LNB is the thing that looks like a flashlight" its on the end of the dish arm, it has the wire comming out of it going into your home, from the dish , i would start with that first , if it works at your friends home , then its the LNB, you can get a new one for around £20 . try that first ......
mick Ireland, October 2009