VL Calibration failed message

Symptom: VL head calibration fails with OP-88145 plate

Possible reason:

The glass chart might become loose from frame and slip / rotate
This can be visually confirmed. Below image show faulty example.
Most of time, correction is possible by holding the plate above the head and rotating, sliding the glass by the thumbs until dots with black center are aligned with the frame.
We assume this is more likely to happen to demo unit due to vibrations during transportation. (customer plate possibly not affected)
At the moment, repair service is not available for OP-88145, so either adjust manually (calibration will pass) or apply for new OP-88145 (B&L)