Peter, here is an easy way to test your 3-in-1 to see if that is the cause of your motor problem. Pull the throtte wire and the rudder wire from the 3-in-1 out of your receiver. Plug in the helicopter battery and use a voltage tester with very thin needle like leads to touch the red & white terminals of each of the leads from the 3-in-1 that plug into the receiver. (Look at the end of the wires coming from the 3-in-1 there is a black plastic plug that plugs into the receiver. Look closely and you will see tiny openings in the plastic plug on one side were the metal of the wires inside is exposed. This is where you touch your leads from the voltage tester). There should be 5.0 volts between the red & black wires on each lead. If you get no reading then there is something wrong.
Also, I have read in the Lama 4 forums that many people break in their motors by hooking a 1.5 volt battery to the motor terminals and letting them run for a while. (Remember that the Lama 4 is a 7.4 volt helicopter not an 11.1 volt). You could try this same approach to see if your actual motor is bad or not. Get a battery and touch the leads from the battery to each terminal of the motor and see if it powers up. I'm just not sure of what voltage to use. I don't think that 1.5 volts would be enough. I would start off with maybe 5 volts, but don't use more than 11 volts.
Tom