dm500s won't lock

hi again it me lol,new prob with a new box i give up on the openbox for now,i have a brand new dm500s black with a signal prob,when scanning it carn't lock but the signal goes up to 70/80% now it should lock at that %,i have change the q72 smd transister but dident make any diferance, i tuck it off another working 500,now its back on the 500 and works fine so maybe its not that thats the prob,i resolderd the tuner but still does the same,so does anyone know what els it could be,this box is from the same place i got the openbox from.
thanks