At random times, ARC will just pretty much disable torque on all of my Dynamixels. I don't think it's a issue with power or the Dynamixels themselves, since it'll happen at random times even with a single servo connected. They'll just sort of all lock up and then stop reacting to commands from the EZ-B, but they're still powered and not giving any signs or messages about being overloaded. It appears that the torque is just being switched off from the short amount of detective work I've been doing. The EZ-B also does a low hum at the point of "lockup". It gets worse when the camera is plugged in and even worse when the camera actually running. I've went through the entire power range that Dynamixels work with (9v-12v) and it happens about the same way with all voltages.
I have all of the power coming from a Dynamixel hub to the EZ-B, could that be a problem? I can't seem to figure out why this is happening since I really don't know the actual EZ-B in hardware terms. I'd be glad to give you more info if you need it, however.