I have an older model crown turret that is giving numerous codes all pointing to the srvo valve, servo motor, lvdt and servo card. I have swaped out all these parts from another functioning truck and no luck. when you first start to raise the platform the carraige goes up about a foot first then the platform as you increase the raising. I also changed out the raise,lower handle potentiometer as well just to rule it out.the raise/lower of platform and carraige do not respond correctly and when lowering the lift motor spins backwards making alot of noise. no sparks from motor, brushes are good and im stumped.

any help would be greatly appreciated.