Hey, I have a JG M4A1 from Velocity Arms, and a while back the gun just stopped shooting. No sound was made when pulling the trigger, and it wasn't the battery, fuse, or motor so I figured that it would have to be a wire. I opened up the gearbox and noticed that the red wire was detached, but I'm not sure what it is supposed to be soldered to.
Looks like the thumbnail isn't working... here is the link to the picture
http://www.flickr.com/photos/53026379@N05/4894892342/