ARRIS/SURFboard → SB6120 Username / Password Issue

I picked a 6120 up off craigslist and when I try to go to 192.168.100.1 it asks for a username and password.. the standard admin/motorola doesnt work and RCN is not able to activate it. How can I wipe this thing to restore to factory defaults?

From what I know about mine, there is no way to set a password on the modem on that model, now there are other models with wireless router built in, try admin/password or admin admin, or even admin leave password blank.

I have an SB6120 (on Cox) and it has never asked me for a password when logging in. Perhaps that feature is part of the firmware used by RCN- I wouldn't know.

it should be user/user, or user/password. Its a feature employed and enforced on an ISP by ISP basis. Try lots of different combos, and for the life of me, i cant understand why anyone would enable this, since you cannot change settings of the modem(unless its a hacked modem to allow uncapping), so the password is unnecessary.