I just finished building an 80'' extra 300S with a DA 50. Y'day when i tried to start it up for the first time, the engine ran well for the first 30 secs. Then all of a sudden the throttle(hitec standard) and both aileron servos( 625 MG) started to jitter like crazy. I thought maybe its interference so i shut it down. When i started it for the 2nd time the same thing kept happening. the 3rd n 4th start bore the same result. On the 5th start i tried to troubleshoot the problem n narrowed it down to 3 issues:
1. a bad servo amongst all three (possibly throttle servo)
2. Loose plug connector
3. Bad servo extensions

Im new to gassers so pls tell me what the possible reasons could be? am i looking in the right direction? what can i do to sort out the problem?