TM MP5 Full Auto, but no Semi
 

I've got full auto fire, but when I select semi, I get a clicking sound, but no fire. Just fully charged the battery. I was able to shoot about 6 rounds initially before my mag ran out and when I reloaded, that is what happened.

Is this a motor issue or a selector issue?

Definitely not motor if you can fire on full, likely something worng with the selector switch or the wiring assembly.

Likely going to have to tear apart the gearbox to fix it. I would recommend you track down a gun doc if you are not one your self.

My two cents.

Have to make sure the selector is in the semi position once you settle the lower receiver into place enough to push pins through the mechbox. If it's pointed at full, it won't move properly enough to get semi.

MY two cents! ;)