Please go to Diagnostics | Signal Levels
Place the white tile at the port and Press Read
For reference purposes Xa, Y, Z should be approximately 45,000 counts and Xb should be approximately 20,000 counts. Lamp Age, system cleanliness, presence of a glass or plastic window at the port can cause these values to vary.
If the values differ greatly from those shown, replace the lamp. If values still do not come into range then record all four values.
Note that each White Tile has a Min White threshold associated with it, typically in the range of 10,000 counts, meaning that if any of the four values you recorded were under 10,000 then the White tile would not be recognized. These are occassions where you may be instructed to lower the Min White value to 500 counts below the lowest value you recorded to be able to standardize the sensor. Doing this would allow "emergency use" of the sensor until proper service could be performed.
If your signal levels appear to be random values (ie. Xa = 13,000 Y = 64,000 Z = 45,000 ), or if any one channel is 0 then send an e-mail to Service@HunterLab.com , include your contact information, instrument serial number and signal levels for each filter. You will be contacted with an SRO and instructions to return the sensor to HunterLab for repair.