I have 5 Sanwa SRG-BLX servo's that have had their fair share of drift action in 5 years. Three of them recently crying out for maintenance after that one too many collisions.
Servo savers do a job. The BLX as you can see here has one weak link.
And this is it. All teeth missing from the small plastic spur gear.
unfortunately you have to replace the whole set.
So job done...
2 servos rebuilt and back in action. 1 to go.