From your description, the problem could also be caused by a few mechanical functions.
1- Make sure your feeder tube is straight, and/or not inserted too far into the feeder tube.
2- If you still have the same problem, check the drive guide (the area the bisquettes travel on to the burner), and clear all loose wood chips so the push plate is free of any obstacles. By regularly cleaning the smoke generator, bisquette jamming and undue wear and tear can be avoided.
3- The problem could be a worn motor, and/or worn linkage. To test this, remove any bisquettes and the feeder tube. From the top of the generator, place a finger down the feeder tube opening; making sure your finger is in front of the push plate. Now push the wood advance button let the plate push up against your finger. If the motor is good, it should put enough pressure on your finger to give you the impression of its going to squish my finger, before it will retract. If the plate stops instantly or turns around with very little pressure against your finger then the motor is worn out and should be replaced. Before ordering a new motor, check to see if the linkage is worn. Inspect the brass colored arms and pin on the motor to make sure they do not have excessive play in them.
4- A less common cause could be the push plate rails may need to be realigned. Dethatch the generator from the cabinet. Check the sides of the pusher plate, and rails. If you see wear marks on the side of the push plate and rail something is out of alignment or bent. On the side you see the wear marks, loosen the two screws that mount the motor mounting bracket to the black plate do not remove them just loosen them. If the wear is on the left side loosen the two screws on the left side of the push plate. If the wear is on the right loosen the two screws on the right side. Make sure the railing is loose enough to move. This may require some cleaning and removing built up smoke residue. Then push the wood advance button a few times this will let the motor align the push plate find its own center line. Carefully tighten the screws, without moving the rail. Push the wood advance button to make sure the alignment is correct.
NOTE: Another sign that there is a misalignment problem, is that the generator will work fine for a while or for the whole smoke, then suddenly start having problems with the advance system. The motor runs both clockwise and counter clockwise. Whichever way it turns it puts more pressure on one rail than it does the other. So if it turns in the direction that puts more pressure on the misaligned rail, it will travel partway then retract. If the motor turns in the direction that puts more pressure on the properly aligned rail, it will fully cycle without problem.