If the plastic sensing surfaces of the edge detectors need cleaning, you may wipe them with soapy water or isopropyl alcohol. The edge detectors are small, black cylindrical housings about 3/4 inches in diameter mounted inside the light shade. Be sure to keep liquid out of the sensitivity adjustment ports.
Click here for instructions for troubleshooting your edge detectors.
If the edge detectors still do not seem to be operating properly, instrument service may be required.
If additional assistance is required, you may contact HunterLab.