We just got a second dryer we'd been using for years suddenly would tumble but not heat up. Thinking it was the age of the dryer and able to find a newer one for cheap, we decided to replace the dryer instead of fix it. Now after a couple of months, this dryer is not heating up suddenly. Have cleaned the filter, took the back part off and cleaned the lint out (which wasn't that bad) but no luck. Any ideas why this would happen again?