if you have conect another box through loop , that maybe causes your problem , if not your problem is probably hardware
Check your diseq , lnb and cable .... it must be some of that
if you check your lnb, diseq and cable also check your f conector...
maybe your xml file is out of date try another one..... , also you can try manual search this tp or manual search example only one sattelite , if nothing happend than make backup of your image and try another one.....
what type of lnb you have ?
on 500 black clones with switch for example ,old lnb are no good (had same problem with 3 clone receivers )
and on what frq it does it ? (horiz... or vertical )
I have 4 antennas positioned in 4 different positions.. Regarding with a DISeqC Switch.. all things are ok , but i think it's in tunner .. .. all channels agc 0% ..