strange signal problem fo dm500s

hi all
I meet strange signal problem in my new dm500s , it cans detects any signal of canalsat in astra 19° , I through its lnd I change all lnb cable connector I try with two old reciever the signal is lot of good I got all channels more then 1000 but with fm500s only 200 channels, I try many lnd setting in the gemini 4.5
1-one satellite direct conection
2- via diseqc
3- manual lnb setting...

no one success
finaly I did strange test which success for me may be this can help some peoples who meet the same problem.
I put a wire in my the in of my old box I use another wire from the out of my old box to the in of my dm500s and rescan I got all channels with all canalsat frequencies .
I am wondering how can I fix dm500 problem without depending in my old box.

any suggestion will be really appreciated

regards