Factory reset the modem on Sb6141.

SB6141 doesn't have physical reset button the modem to perform hard reset so in this case you need direct connection like computer or laptop to connect to the modem LAN port using ethernet cable then disconnect coax cable from the modem. On direct connection try accessing modem GUI and follow the steps mentioned on the below article to get into GUI.

http://arris.force.com/consumers/articles/General_FAQs/SB6141-Factory-Reset