CONCERN: Customer reports dryer has a burning smell while running. CAUSE: Internal dryer cabinet filled with blow by lint. CORRECTION: Disassembled dryer and cleaned internal dryer cavity and reassembled unit. Operation is now normal. CONCERN: Dryer takes too long to dry clothes, dryer does get hot though. DIAGNOSTIC AND CAUSE: Tested dryer for proper heater element operation. Heater operation is normal. Inspected heater thermostat operation for short cycling condition, thermostat is short cycling. Inspected dryer air flow at the duct flume, air flow is normal at this time, no signs of flow restriction. Cause, Wall vent clogged with lint. CORRECTION: Performed dryer vent cleaning, tested for restrictions, operation now normal