Fault Phenomenon: LiuGong HBT90 display screen is normal when cold. After reaching operating temperature (high cab temperature), the screen flickers frequently, parameters display garbled code, and eventually goes black.

Troubleshooting Process:
– Checked display screen power supply wiring: no damage, good grounding.
– Checked host software version: latest version, no known bugs.
– Checked backlight drive circuit: voltage stable when cold.
– Measured backlight drive voltage at operating temperature: found voltage fluctuates severely.

Root Cause: Capacitors on the display screen driver board leak at high temperature, causing unstable power supply.

Required Parts: Instrument display screen assembly.