Tune failed, and weak signal on affected box

[Hamram]

I have a problem I've never had before, and I've read "all" the threads I could find about tune failed, but I can't find any other thread about a problem similar to mine.

One of my Vu+ Duo's are behaving strange. I get signal on only a few channels. I Use Thor and Sirius, and I get some channels from both positions, and I get both V and H channels. On the channels where I get picture, I can see that the signal strenght is only 2/3 or 1/2 of the strenght it usually is. On the channels where I get "Tune failed" there's no signal at all. If I hook up my other Vu+ on the same cables, everything is OK, so I'm pretty sure there's something with the box. I've tried all possible settings and channel-lists, but still no luck. I even cloned it with my 100%-working box, but no action, except from a few channels. Sometimes I get a few more channels, and other days a few less. To me it seems like the tuners (both are affected) in the box are not able to "read" the signal good enough, as it get's only a weak signal, compared to my other box.

Any suggestions..?