Cal Error 4.##; Cell Change Warning

The above error message (## may be any number between 01 and 16) in most cases requires that the instrument come in for service. It means, that the instrument is seeing less reflection on the white calibration standard than it originally saw (when configured at the factory).

Be advised however that there are several conditions that may produce these error messages. Before returning your instrument for repair please check all of the following:

 

If none of this helps, the instrument must be sent in for service.