After posting my problems with Hitec 5645's and no response from Hitec, I took matters into my own hands and found the problem with my digital that would lock, up jitter and perform all manner of nasty interations was in its assembly. I opened one of the servos and found that one of the chips had solder bridging two of the prongs on the chip. I cut and cleaned up the bridge and presto the servo works rock solid. I opened up my other problem child and found the same problem! Both of the servos worked flawlessly after this sloppy work was cleaned up. I wish Hitec would respond to all the problems with these digitals.