Generally speaking most of the miscommunications issues between the modem and CMTS are because a high tx or return,or maybe threre's no return at all. after like you said power surge ocurred may sure everything is good to go and remenber return or tx higher than 55dBmv sooner or later is going to give you problems because no communication with the CMTS or there's no ranging in between the amount of packects that you sending and receiving= modem will not work or internet on and off issues.
Robert.
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