Power HD brand servos INSANELY twitching

Hi guys, I've been having trouble with these Power HD 8312 & 8310 servos that I purchased (2 of each). They are all twitching and jittering like crazy if I try to set it to anything past 50 or 60 degrees.

The exact same setup works great for my other digital servos, but the two Power HD 8312 TGs and two 8310 TGs that I have exhibit this exact behavior. Additionally, I had also tried Power HD 8310s and they did the same thing. Is there an issue with my setup? Do I need to do something else to get these servos to work correctly?

I've also tried the following: - Wiring the servos to a 6V battery pack (4 2500mAh NiMH rechargeables that were just fully charged) - Adding a 10nF cap between common ground of the Arduino and servo - Connecting the servo to the 5V of the Arduino

Here's a video of the issue: http://www.youtube.com/watch?v=sYoMONo185k

(I realize that I accidentally wired the battery pack's positive lead to the 5V pin of the Arduino in the video, but I fixed it after and didn't feel like re-shooting. It still twitched).

The battery pack cannot supply enough current for the servos and the voltage is dropping. Use a heftier power supply, budgeting at least 1 ampere per servo. NEVER try to run a motor or servo from the Arduino 5V terminal.

Awesome! Do you have any suggestions on something that would be portable?

I buy RC battery packs at http://www.all-battery.com/ Depending on your servos, you will probably need a switching voltage regulator capable of handling sufficient current.

don't power the arduino and the servos from the same power supply if possible. Below is the typical servo external power setup. The twitching may be due to the digital servos not being programmed to move more than +-45 deg. You may need to reprogram them to move a full +-90 deg.

Is there any link that would tell me how to reprogram the servo to move +/- 90 deg? I searched google but found nothing…

datasheet says 0.180 deg... (and 0,7A!!!) http://www.pololu.com/file/0J694/HD-8312TG.pdf