The Waratah AS667D Head Module is a control board that interfaces the hydraulic drive and motor assemblies of a forestry head attachment, typically housing an embedded PLC, motor drivers, and sensor inputs for position and pressure feedback. Common failure points on this class of units include degraded power supply rails (leading to intermittent operation), relay or contactor wear causing loss of hydraulic command signals, burnt‑out MOSFETs in the motor driver section, and misaligned or fouled limit switches that trigger fault codes. First‑check diagnostics should verify the 24 V DC rail integrity with a multimeter, inspect all relays and contacts for corrosion or burn marks, and review any stored error logs on the PLC to pinpoint the exact subsystem fault before proceeding to component replacement.[oss-gpt-20b]