Gun won't shoot. No noise, power, nothing. Even with the battery fully charged. I removed the full stock but there was nothing wrong with the wiring. I checked to see if the fuse might be blown but I didn't see anything wrong with it. I've also removed the grip's bottom plate to see if the wires may have disconnected with the motor... but no. I tried a friend's battery who has the same as mine, but even that didn't work. The day the gun stopped working, there wasn't any grinding or scratchy noise. I want to diagnose the problem with the gun before having to replace any parts, and I don't want to open the gearbox without knowing what to do. If you must know, the type of gun is a Echo1 STAG-Arms Mod4 M4 TC. PLEASE HELP!!! Thanks!