Potsdam Fire was activated via land-line for a report of a chimney fire at 131 Main Street at 1212 hours. Engine 49 (Fenton) was enroute immediately and arrived on scene 1215 hours. 1st Assistant Chief David McGregor took Command and requested Tower 5 and Rescue 14 to respond. Tower 5 (J. Corbett) and Rescue 14 (J. Robar) responded. Firefighters began to set a 24 foot ground ladder and a 14 foot roof ladder up on the A side to gain access to the roof and to the chimney. The thermal imaging camera was used to check a the upstairs and around the fireplace to look for extension. Firefighters cleaned out the fireplace and noticed debris smoldering just above the fireplace. Firefighters tried using a dry chemical extinguisher to extinguish the fire but were unsuccessful. Firefighters then used a grinder to remove the chimney damper which had fallen to a closed position, and could not be opened due to a substantial amount of debris which had fallen on top of it. After removing the damper, firefighters discovered a quantity of smoldering debris and removed it from the residence and used a wet can to extinguish it. Firefighters used salvage covers to protect the interior of the structure while they cleared the remaining obstruction in the flue. Potsdam Fire was back in service at 1407 hours.