<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">cletusclutch </div></BLOCKQUOTE>
I had a similar problem and also replaced the LNB then the cable itself with no joy. Everything worked with the external dish connected, so I really thought the problem was associated with the rooftop dish or associated wiring.
I finally found the A/B switch was bad.
Having never seen a problem with one,that was not what I expected.
Clay WA5NMR - Ex Snowbird - 1 year, Ex Full timer for 11 years - 2004 Winnebago Sightseer 35N Workhorse chassis. Honda Accord toad.