Display PP41_ screen whitening problem

We are currently facing an issue with multiple PP41 QVGA display units and would appreciate insights from the community.

Problem Description:

During operation, the display suddenly turns بالكامل white (bright backlight ON), with no numeric or alphanumeric characters visible. The system otherwise appears to be running.

Troubleshooting Done:

- We replaced the QVGA display itself → issue persists

- We replaced the PCB (PP41_RIET/2) with a known good board → problem is completely resolved

This strongly indicates that the fault lies within the PCB rather than the display module.

Request for Support:

We are looking for guidance on repairing the faulty PCB instead of replacing it entirely. Specifically:

- Which components are most likely responsible for this type of failure?

- Are there known failure points (e.g., voltage regulators, capacitors, driver ICs, or communication lines)?

- Any recommended test procedures or measurements to quickly identify the defective section?

Additional Context:

- The issue occurs under running conditions in an industrial environment

- Multiple boards are showing similar symptoms

Any suggestions, repair experiences, or technical advice would be highly appreciated.

Thank you in advance for your support.

Not sure if anyone in Community can really help you there. B&R does not publish PCB schematics, so component tracing must be done by reverse-engineering. Consider reaching out to B&R’s repair.