In this video, Aaron runs us through how to troubleshoot a steering servo that's not working.
This video in blog form: https://hobbiesdirect.com.au/index.php?route=mblog/article&article_id=38&page=2
New servos:
https://hobbiesdirect.com.au/electronics/radio-gear/servos/
Radios:
https://hobbiesdirect.com.au/electronics/radio-gear/transmitters-and-receivers/
Receivers:
https://hobbiesdirect.com.au/electronics/radio-gear/receivers/