shutter

Hello all,I have an issue where, occasionally, and randomly, some my VL3000 spots are delayed in opening the shutter when they’re told to open. Usually by 2-3secs (seems like eternity). Sometimes it happens with a fade up, sometimes with a snap on. It’s almost never the same couple fixtures...

I am at a theater that uses stock shutter and frame assemblies. but no sill irons. Isit possible to use a door without a sill iron or is there an alternative to the sill iron if there is not one there?