Sorry I got here late and the repair decisions have already been made but Russ Knotts at ESL Repair in Chardon, Ohio has replaced a number of panels in my 2905’s. It might be hard to persuade him to do future work on Quads as he’s getting a bit further up in years but he knows what he’s doing, without question.
One thing I’d like to pass on which may extend the life of Quad ESL’s except for the 57’s, is to turn them off after you’re done playing them and then turn them on about a half hour before listening to them again. This will not work for the 57’s because they need about a day and a half to fully charge.