A very common fault is a worn out capacitor. Its the thingy that kickstarts the drum left or right- so its always working hard. Without it the motor wont turn. It is usually fixed to the side of the motor by a simple fixing and has a couple of spade terminals. A common size of unit for domestic T D's is 8micro farads (or Mu).
Google "capacitor for.......etc" or go to www.espares.co.uk they even have them on Amazon.
Expect to pay £6 to 12.
Geoff in Wales
October 2012