I'm not sure about this engine,, an RS -3 with a 3 volt board started to smoke and we immediately took it off the track.
Took the shell off and can't find anything out of order, Feature and factory reset , everything works except one motor , the one with the tack reader, It will every now and then move a little bit. nothing binding truck or shorting out. . won't move in conventional either except for the odd spurt.
How can you tell if a motor is bad and do motors go bad very often???? I do have a spare but... don't feel like changing it out unless I really have to.