The Rexroth Hydraulics 1MC1‑16 R978905570 Mobile Digital Controller is an embedded PLC used in mobile hydraulic systems; it manages valve logic, sensor inputs and actuator outputs via a digital I/O network. Common failure modes for this class include power supply degradation (brownouts or voltage spikes), faulty I/O modules (shorted contacts or open circuits), and board-level component failures such as burnt capacitors or damaged ICs that cause loss of communication or abnormal error codes. First‑check diagnostics should verify the 24 VDC power rails with a multimeter, inspect all I/O connectors for corrosion or loose pins, and review the controller’s diagnostic LEDs or serial log for specific fault codes before proceeding to board inspection or component replacement.[oss-gpt-20b]