I had a similar problem with my 10SD. I changed from 72Mhz to 2.4 and my analog throttle servo smoked! It became very hot and shorted out. I replaced with another analog servo and it started to heat up again worked for a short while and shorted out. I changed the servo to a digital version and my problem went away. I was using the 10 channel Rx. All the other servos are digitals with no problems.