Originally Posted by micros
I've had this a few times. Try cleaning the cogs of the drive gear. Although the fit is tight, fine dirt can build up between the cogs. Avoid using something metal as it could damage the brass. I use one of those triangular wooden toothpicks. Also check the teeth of the white plastic gear.
Just FYI - I use a stiff bristled artist brush about 1/2 in. dia. Just brush downward while slowly rotating the gears to clean both gears at same time. Only takes 2-3 min for whole craft.
Also...re: intermittent connection problems....I had one I traced to where the boom wire connects to the motor plug. Finally found it with a continuity checker. Must have been a bad solder joint. Stripped the black insulation, re-soldered, covered w/ glue, AOK since.
Hope this helps.....fly on......