The Taylor Fulscope Controller (e.g., 49P314‑25B) is a field‑deployable chart recording and PID control unit used for process monitoring and data logging in industrial settings. Common failure modes include power supply degradation, relay or contactor wear, signal input drift, and mechanical wear of the pen drive or chart feed mechanism; overheating from improper mounting can also cause internal component failure. For troubleshooting, first verify that the 24 V DC/AC power rail is within spec and check for any blown fuses or tripped breakers; next inspect all I/O terminals for corrosion or loose connections and confirm that the signal conditioning inputs are receiving correct voltage ranges; finally review any stored error codes on the controller’s display and perform a visual inspection of the pen drive assembly for mechanical blockage.[oss-gpt-20b]