In my apt we have a ten year old electric dryer. Not too long after I moved in, the dryer would only dry when knob was turned to 70 or more minutes. I had been using it like that for a about 2 years and just recently, it stopped drying completely. My landlord took the whole thing apart, and checked everything, said all parts were working properly, the motor, heating coils, and thermostat. After 3 days, he finally figured out that it was the dryer knob. He didn't replace it, just messed around with it and now the dryer works but again I have to mess with the knob and usually turn it to 70 minutes in order for it to dry. The problem now is that the dryer makes an awful squeaking sound when drying clothes and it did not do this before. He came back and took it apart and put the drum back in and it seemed to stop but now 5 minutes later its still doing the same thing. What could it be?