The Whitfield PSC120A‑3926 (part 12055902) is the digital control board for pre‑1999 Advantage II‑T, III and Plus pellet stoves, providing temperature regulation, fan control, and ignition sequencing. Common failures include a dead or blown main power relay, missing igniter connector on newer models, and burned trace damage from over‑voltage or shorted sensors; the board often shows no output to the furnace or erratic fan operation. First‑check diagnostics: verify 120 V AC input at the board terminals, inspect for visible burn marks or cracked solder joints, confirm that the igniter connector is present (or replace with a compatible 12155912 board if absent), and review any error codes displayed on the stove’s panel.[oss-gpt-20b]