This is often due to a communication fault. Monitor the system to ensure that the current readings are restored. Here, we list the 10 most common problems, analyze their primary causes, and provide detailed diagnostic and resolution steps. Technician inspecting electrical connections inside a solar combiner box 1. The solar combiner box maintains all the wires and other components that reach the inverter in. In the daily operation and maintenance of photovoltaic power plants, the combiner box often fails to communicate normally due to various problems, resulting in the untimely update of the photovoltaic array status, resulting in power generation losses and hidden dangers. This component is designed to collect and combine the output of multiple photovoltaic (PV) strings before sending the DC power to the. Compare each string's output—uneven readings may signal poor connections, a blown fuse, or a module fault.