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 power flow before and after the SM4 crew services the instrument on orbit.