Definition
The control board (also called the controller or main board) is the central management unit of an ASIC miner. It runs the mining firmware (typically Linux-based), distributes work to the hashboards, monitors temperatures and fan speeds, and handles network communication with the mining pool via the Stratum protocol.
Control board failures can render a miner completely non-functional. Common issues include corrupted firmware, failed NAND flash, damaged ethernet ports, and power regulation failures. Replacement control boards must be compatible with the specific miner model.
In Simple Terms
The management board in an ASIC miner that runs firmware, coordinates hashboards, and connects to the network.
The brain of an ASIC miner that runs the firmware, manages hashboards, connects to the network, and communicates with the mining pool.