What to do if Optima Scale OP-900A displays ERR3?
- PPatrick FigueroaAug 21, 2025
If your Optima Scale Accessories shows 'ERR3' during calibration, this indicates a negative input signal. First, check all wire connections. Second, check the load cell. Third, recalibrate the scale. If these steps fail, a PCB replacement may be needed.






