Cosmo are you using a multiswitch with your old primestar lnb, to get both polarities? If so, and it's still erratic, it might be dying. Sounds almost like water in the connectors somewhere though, if it works and then drops out. The other guys were suggesting you unbolt the feedhorn from the old lnbf, and use it on the new one, they're tiny little bolts, I think on the 84E they have allen-screw type heads. Gabs has the idea though, for a great replacement, use one of the Direcway or DirecPC lnbs, they match right up and are excellent lnbs.