Cleaned exhaust duct, but only from the dryer/laundry room side. Replaced thermal fuse. Unit worked for about two loads and thermal fuse blew again. This time I cleaned the exhaust vent on the roof of my 2-story house. It was found to be partially obstructed and I was able to remove a significant amount of lint from it. Also, I researched the problem and followed someone's advice to replace the cycling thermostat together with the thermal fuse if the thermal fuse blows. So far it has been working, but my wife and I both feel that it is for some reason operating a little hotter than it used to. It is working so I am leaving it alone for now. If it should blow again I will have to look into the rest of the parts in the heating system. i.e. temperature control, dryer timer, heating element and dryer control board.