NEC NC1600C Service Manual page 232

CIRCUIT DESCRIPTION
Description of Operation of L-SENSE PWB Circuit
An optical sensor is provided at the center of the outside of the optical engine Hold mirror.
The output of this sensor is A/D-converted at PJDIV PWB to which L-SENSE PWB is connected.
CPU PWB recognizes the lamp brightness in accordance with the A/D-converted value. This value is also used
as information on functions such as Lamp feedback and Lamp bulb adjustment.
"Confidential, Do Not Duplicate without written authorization from NEC."
8-27