The Sumtak FRR902L7DG Pulscale is a high‑resolution rotary encoder (pulse scale) used for precise position feedback in industrial motion control systems. Common failure points include power supply degradation, signal line insulation breakdown, and internal IC damage from overvoltage or electrostatic discharge; these often manifest as erratic pulse counts or complete loss of output. Begin diagnostics by verifying the 24 V DC input rail with a multimeter, inspecting all wiring for continuity and proper termination, and checking the encoder’s serial interface for error codes or abnormal signal patterns. If issues persist, proceed to isolate the ICs on the board and test the pulse outputs against a known reference encoder.[oss-gpt-20b]