Any electrostatic will be considerably less efficient than anything Klipsch makes. Here’s an article that may help you understand the Quad 63’s design & goals: ( If some of the panels aren’t functioning, you may want to contact: ( or (     You may find this of interest: (
Talk to Kent at Electrostatic Solutions; he would be among the very best at diagnosing and potentially repairing.
But according to Doug you should just buy new. 

"I will be blunt. Old speakers sound better since... never. The only way you will make them sound better is through an improved system upstream."