I have changed the controller board and the servo to my JJP Hobbit's Dragon mouth assembly. We can get the servo motor to move back and fourth to the Two Coordinates/Angles that we can set in the software during test. But when it is time for the servo to move during speech test it does not work correctly. This is without linkage attached to the Servo. Nothing attached at all. New Servo motor too.

When in the test mode, and we press "Start" button I think the game does a quick voice sound and the servo is suppose to be moving then. But it isn't.
Spend hours on this scratching my head and called Ken at JJP a few times.

Well, the potentiometer in the servo will eventually get worn. Or the motor inside goes bad.
I expect One day everyone will have to swap the servo motor. I did. AND the controller board.
Maybe you just need a new motor?
Still frustrated at this thing.

Here is the OEM Servo by the way

https://hobbyking.com/en_us/hobbykingtm-hk15288a-analog-servo-bb-mg-9kg-0-20sec-51g.html?utm_source=google&utm_medium=cpc&utm_campaign=google_us_shopping&countrycode=US&gclid=EAIaIQobChMIuZji-ens7gIVDKGzCh39ugFMEAYYASABEgL4OfD_BwE&gclsrc=aw.ds

ebay.com link: RC HobbyKing HK15288A Analog Servo BB MG 51g 9kg 0 20s