WiFi Extender for home security system.

I bought the Netgear WDR3000 WiFi Extender which is the model recommended by Comcast. When I plug this into the security router it powers up and the modem number 1 lights up.

Now the tough part.

Whatever I seem to do with my alarm console I just cannot get rhe extender to connect to the security modem.

What is even worse is that th admin password has been changed so I cannot look at th settings on the modem.

Thinking about returning the whole darn system as it is no use to me but was hoping someone could offer me som help.

I have tried

1. Wps connection
2. Wired ethernet
3. Extender works fine when connected to main wifi modem