The filter mechanism was checked and realigned, but no specific cause was found for the problems experienced before, though no problems have been reported since. It should also be noted that the software was modified such as to limit any filter movements when the instrument is not in use.
We are considering including the filter mechanism under the control of the new TCS instead of the old PLC. One could then add a mechanical alignment switch to the filter mechanism to properly align the filters at all times.
An H-wide filter has been was added to the permanent StanCam UBVRI filter set.