I have a brand new futaba 3pks that started doing that with the th servo the second week i owned it, & i sent it back to futaba, the said the fixed the problem and sent it back to me with no explenation. so it worked fine for the last two months then it started doint it again really bad. so i am pissed off i did not pay $350 for a radio to act like a piece of crap, but it is back at futaba right now & they are going to replace it. it is not common for a 3pks to act up like that but sometimes they do. but it is not your servo's man it is in your TX.