Moleculon fuse

Despite being an integral part of both Autobot and Decepticon   technology, moleculon fuses seem to be extraordinarily prone to burning out and often need to be replaced.

Transformers: Fall of Cybertron
When Perceptor was having trouble getting the power back on, he noted that one of the moleculon fuses needed to be replaced. Unfortunately all of the replacements were down a short corridor with an opening subject to regular electric charges, so Optimus Prime had to be quick in retrieving it. Following the launch of the Ark, Ratchet got Bumblebee to carry a moleculon fuse through half the ship to fix the lift.