A quickly testable subassembly with redundant isolation devices usable in a liquid crystal display has a pair of coplanar spaced apart alectrode segments connected to one or more-isolation devices. Address lines are connected to the isolation devices or the electrodes. The isolation devices and electrical connections to the electrode segments can be quickly tested prior to assembly of a complete display. Redundant isolation devices are formed on the subassembly and inoperative isolation devices can be replaced by associated redundant isolation devices. A method of quickly testing the subassembly and of replacing inoperative isolation devices, and several alternate quickly restable subassembly geometries are also disclosed. A self-selecting redundant geometry and method are also disclosed.