The Whitfield PSC120A‑3926 is the digital control board that governs temperature, fan, and safety functions in the Advantage II pellet stove. Common failure modes for this board include a dead power supply (brown‑out or missing VCC), burnt capacitors or ICs from over‑temperature events, and faulty sensor inputs such as limit switches or thermocouple connections. First‑check diagnostics: verify 24 V DC input to the board, inspect for visible damage on the PCB, and review any error codes displayed on the stove’s LCD or transmitted via its diagnostic port. If power is present but operation remains erratic, test all I/O pins against expected logic levels and replace any failed components identified by a multimeter or oscilloscope.[oss-gpt-20b]