I have an RS V1 which I'm pretty sure has a bad motor controller chip, though I'd love someone to tell me otherwise.
Symptoms: On powerup the eyes light and it makes the appropriate grunting noises, but there's no movement. Likewise when receiving commands from the controller, the eyes and sounds are fine but no movement. The touch sensors all work and the hand LEDs light normally.
Opening the chest I see no loose connections, bad solder joints, or anything else visibly wrong. I've got the RS hooked up to a bench power supply at 6V, and see that he's momentarily pulling more than 1A on powerup. When idle he's pulling about 0.6A. That's way more than I'd expect. The motor controller chip (U3) is scorching hot to the touch. I've individually disconnected all the motors and the symptoms persist, so I don't think there's a short somewhere.
So, like I said, I'm pretty sure it's the controller chip. But I'd really like someone to tell me, "Oh, that happens when a transistor is blown. Replace transistor XXXX and you're golden."
Mainboard rev 6008-10C, if it makes any difference.