Fault Phenomenon: Zoomlion ZR280 rotary drilling rig operating the mast left/right tilt, response is slow or cannot adjust to vertical.

Troubleshooting Process:
– Checked tilt cylinders: cylinder internal leakage or piston rod bent.
– Checked angle sensor: tilt sensor signal drift or open circuit.
– Checked control valve: proportional valve spool stuck.
– Checked hydraulic lock: bi-directional hydraulic lock internal leakage.

Root Cause: The mast tilt angle sensor has zero-point drift, causing the control system to misjudge the mast position and issue incorrect commands.

Required Parts: Recalibrate or replace mast tilt angle sensor.