Has the motor died? Simpson Sirocco 455?

The dryer was heating up quite a lot so we believed it was the thermostat... ran it on warm rather than hot and it worked well... then it started to get colder. One evening while it was going we got a 'bang' more like a popping sound followed by a very strong burning smell. Haven't tried to use it since. Is it the motor? And if so where can we get another one and how do we replace it?