N300 router (can't login router)

I had my N300 router set as repeater to extend the range of Wifi in our house, the main router is RangeMax Dual Band 3300, They are working fine. The wireless channel was set at 11, now I would like to change it to 5, I can do it on the RangeMax 3300 by login on to the router, but I can't login on the N300 router by type 192.168.1.1, Please help