Check out what Allan said about 'HRS' especially if the servo is 'buzzing'. I use a Futaba 3PK that has an HRS mode. If you are set to use HRS and are using an analog servo like a 225, it will burn it out pretty quickly. An HS81 will even burn out quicker! Futaba analog servos seem to have a bit more tolerance, especially if they are larger, but they too will eventually burn out. Also, I thought I was ok when I set the modulation to PPM when I first put several models in the xmtr, but when I added a new model, I did not notice that the set-up defaulted back to HRS. The instructions are not the most easily understood when setting the modulation. After you enter it the set-up screen you have to make sure you power down and back up to make sure the PPM mode is actually stored. I now check the modulation on the screen every time I turn the xmtr on. If you can rule out 'HRS' as a possible cause, then make sure there isn't any binding. I had an HS225 on a VS1 tunnel throttle cable that corroded just enough to slow the cable travel down and the servo burned up after a couple of runs. I replaced the cable with better material and now inject WD-40 into the sleeve after every days use. RC