A newly bought LNB doesn't work with my old CCTV box don20022014-05-02 00:43:34

I just bought a LNB to replace my old one, but it doesn't work. I am not sure if it is a correct LNB. 

My CCTV box settings: 11780 H, 20760, LNB 10.750 GHZ (these cannot be changed)
The new LNB: Input 10.7-12.75 GHZ; Output 950-2150 MHZ, Noise Figure 0.3dB.

My old LNB still works but the signal quality is not good (about 75). I replaced it with the new one and there was no signal (signal quality) at all though the signal power is strong (197). 3 years ago, I bought the old LNB and it worked immediately after I installed it. I didn't adjust the dish at all.

Please advise me if I bought a wrong LNB this time.  I tried to adjust the dish, but could not get signal with the new one. After I put the old LNB back, I could get the signal (about 75).

Thanks!

Have you moved the dish or new LNB to see if

I did all you said, but I could not see any signal with the new

Is the 78 from new or old one?

From the old one. The new one has no signal.

I bough this one from ebay and it works

Amazon shipped me another one with Ku band. It will arrive tomor