It sounds like it could be your receiver or the dish ( LNB )...
I don't know , it could be either or !!
You are going to have to play around a bit ...
If you can try another reciver from a friend or something first ...
If you have the same problem then I think it would be the LNB ..
But you said you had a spare , if it isn't to hard to get at try changing it ...
Good Luck ...
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