In addition to what IHATEPROPANE has told you you should also seal the area at the top of the auger flight where the cover goes over the pate. This can be sealed with RTV (500
or better).
It is also possible that where the auger flight and drop chute join came loose and the seal there to be broken.
These all fix air leak issues.
If the location your stove is in is a negative pressure zone it is also possible that your fire is air starved and you need to OAK the stove. If you have an OAK on the stove make certain that the screen isn't reducing the area through which air is drawn, this is an issue when certain caps are used to prvent insects and small animals from entering the stove system.
If your stove is piling up it is likely to have entered a reduction burn and this can over heat the burn pot (eventually destroying it) and the stove. Whether this would be hot enough inside the stoves shell to burn the control board I can't say. If the control board is to close to the firebox it might be able to cause issues for the controller. If there are loose connections at the controller they can cause sparking and motors first slowing and then when the connection is remade speeding up after awhile this can lead to the triacs on the control board failing.
I would checkout all connections in the stove. This includes those where the igniter is connected and all motors and snap discs.