Hubble's Advanced Camera for Surveys (ACS) was responsible for many of Hubble's most impressive images of deep space. In January 2007, ACS experienced an electrical short that put two of its three cameras out of commission. ACS contains a trio of cameras: the wide field camera, the high-resolution camera, and the solar blind camera. Each performed a specific function.
This animation depicts the procedure planned to repair ACS. Astronauts will remove 4 circuit boards from inside the instrument, install a redesigned pack containing new circuit boards and then re-route the power going to the instrument.