Panic Attack's shrimec was always powered by a linear actuator in different configurations, that was why it was so slow. Find the episodes with panic attack in a watch them in the pits, thats probably the easiest way to get a glimpse inside.

As for Razer, check the build diary for Venom. Thats was built in conjunction with Ian Lewis if I remember right, so that will be pretty close without actually having Razer in front of you. Venom's beak is powered by a custom lin-ac which also powers the shrimec.

Hope that helps