OK, I'll throw in two cents.
1. Check the
DMX runs, or at least try to see where they run. Did the electricians that were installing the chandeliers, possibly run some power through a conduit that was carrying the DMX cable? It's possible that an induction current could cause enough interference to create a similar problem.
2. Being that it's all the fixtures, it sounds as if you could easily isolae this problem to the control module, in the
dimmer rack. As was stated earlier, a complete shut down and reset of the control module may fix the issue. Again, as stated earlier there are often "reset" procededures to be followed.
Remind the electrical contractors that they are working around some extremely sensitive "high Tech" equipment and they can't simply turn things off willy nilly.