The damage that was done to the DVR before you tried the fix may be causing it. I would replace it one more time this time since the ground wire is already cut it should be okay. A short in the coax well I am not going to say there is no way but its very slim chances the same with a bad LNB one way to check it is feel it if you can safely reach it a lot of times you can feel the LNB will feel warmer than the ambient temp around it.
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