Fault Phenomenon: SANY SY5418THB delivery rate is stable when cold. After continuous operation for 2 hours (operating temperature), the delivery rate fluctuates significantly, eventually leading to a loss of material, with no alarm on the dashboard.

Troubleshooting Process:
– Checked cutting ring and wear plate: clearance normal, wear within allowable range.
– Checked water tank level: level normal, no significant slurry leakage.
– Checked main cylinder reversing signal: pulse width consistent when cold.
– Measured reversing frequency signal at operating temperature: found signal pulse width inconsistent.

Root Cause: The crystal oscillator on the main control board experiences frequency drift due to heat, causing timing confusion.

Required Parts: Main control board (MCU) assembly.