Alright, heres the problem. My good friend got a M4 CYMA(?) and was shooting fine with 9.6v NihM. His battery got weak and I had lipos on hand. I gave it to him for use and it shorted his gun. His gun doesnt have a fuse on it but running Tamiya plugs.
Check the actual tamiya plugs they enjoy melting when paired with higher power lipos. Then check out your trigger posts make sure they are in good shape. If they all seem fine take out his motor and see if runs in one of your guns.
Did you take apart the gearbox? I don't know much about lipos but they do put a massive strain on everything in the gun which could cause the gun to jam because something got lodged in the gears. I have had to repair this on afew of my friends guns and it definantly makes the wires heat up and all you get is a sound like the battery is dead.
It's not the dog in the fight but the fight in the dog.
Hmmmm.... bring the gun on Sat. I'll take a look at it.
Thanks guys, I found the problem. Seem like the high voltage must of "jump" the connectors from the battery to the first solder contact (trigger contact?). That caused the expose part of the solder to bend just a fraction enough to touch the spring for the selector toggle causing it to ground there. I resolder that part and put shrinkwrap on it and the problem went away. :D Now imma happy camper!