Dm800 problem in signal

[software2010]

Real problem

AT the starting point it comes picture and then tuck showing turner failure.After that I check diseqC switch & two LNB are dead.I change LNB & diseqC switch then find same problem ( turner failure)
I Check this box in my friend house.It is working fine with friend box (if we start two box at same time) when my friend box swith off then my box is showing turner failure

What is real problem

Please please please help me

[WOODWARD395]

sounds as if no power to LNB to me as friends box is supplying power until switched of, have you checked voltage settings in tuner settings.