Move that transistor as far away from that little IC as possible, by bending the legs - whatever it takes!
Another thing I do is to strip the motor and gearbox assembly- it sounds extreme, but I have had a couple of motors that were completely seized up, maybe due to harsh conditions or lack of use though (Yes I know, I like pulling motors apart hehe but they are getting old now!). Doesn't seem to harm to give them a good clean and relube, and doesn't really take long!
That trimmer in the processor module might be potential trouble in the future but setting up is probably one of the most sensitive things I have ever had to do lol!