The ACS team will post late-breaking information here regarding the status of the ACS repair (ACS-R) to be conducted during Hubble Servicing Mission 4 (currently planned for May 2009). A recent STScI Newsletter article (PDF) gives a nice overview of the ACS repair.
Astronauts John Grunsfeld and Drew Feustel have completed the ACS Repair during STS-125 EVA 3. The Aliveness and Functional Tests show the new WFC CEB-R to be working as expected and the WFC camera has been returned to operation. During the ACS System Functional Test, the HRC camera experienced an error thought to likely be a result of a short in the power bus. The HRC camera is currently powered down and unavailable.
WFC - SUPPORTED AND DEFAULT GAIN
There will be no changes to the available CCD gain settings for HRC.
For WFC, gain settings of 0.5, 1.0, 1.4, 2.0 (e-/DN) will be available. Only gain 2.0 is supported in Cycle 18.