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To change the belt you need to take the back cover off in the bottom right corner.
Then take all the screws off the back cover and pull it out a bit.
Then slid the belt down the front of the drum and around it.
Then refit the back cover.
Now slid the belt to the back of the drum so it lines up with the motor pully.
Now for the fun part. You need to strech the belt around the motor pully. I use a long screwdriver to do this.
Then once its on refit teh back cover and thats it job done.
But when the belt snapped was the drum stiff to turn?
If so then the front felt seal may be faulty as the glue from there comes off and causes the drum to stick and snappes the belt. If this is the case then the front felt seal will need to be replaced and drum cleaned up at the front.