linkstar s2 modem

Dear sir,
          i have a linkstar s2 rmodem that was working but later discover that the BUC cable was disconnected,i put off the modem and connected but the modem sat led can only blink now just for 2-3 mins  and goes off.i tested the rx out and it gave 17.8v and tx 24v but yet no transmision still.please can you  kindly advise on what to do next.
                     flexcom