IEE 03601‑20‑040/S is an industrial alphanumeric fluorescent display board typically mounted on PLC or controller panels, designed for high‑visibility readout of status codes and numeric data. Common failure modes include loss of illumination due to a failed backlight driver IC or degraded phosphor tubes, intermittent character display caused by loose solder joints or damaged trace connections, and complete blank output from a power supply dropout or blown input regulator. First‑check diagnostics: verify 5 V DC supply voltage at the board’s VCC pins; inspect for visible burn marks or corrosion on the driver ICs and trace lines; and review any error codes or diagnostic LEDs that indicate backlight or display controller faults.[oss-gpt-20b]