weird servo problem?
 

Hi,

I have a friend who's rebuilt my old HPI Savage with a bunch of newer servos for steering and throttle and has developed a weird problem ive never come across:

Just recently, he was ripping around some snow berms and jumps when his TX warned him of a low voltage problem from his RX pack. Immediately after replacing the cell pack the throttle servo no longer operated normally...it would travel to one side (full brake i believe) and you can hear the motor of the servo trying to continue travelling (but cant because of the mechanical endpoint of the gears)

He has a Venom failsafe attached to the throttle servo but this doesnt appear to be the problem and it doesnt involve the servo plug because none of them were changed during the cellpack swap.

Is this a strange potentiometer problem with the servo and it all of a sudden cant find its centerpoint?

Anyone have an idea?