Brother HL-4140CN Service Manual page 326

LCD
TMP
HUM
MAC
BT
Note:
If the sensor detects the abnormal value, the printer displays "NG" on the LCD.
(3) Change the detecting conditions to check that the indication on the LCD changes
according to the sensor status. For instance, insert paper through the registration front/
rear sensor, open the front cover or the back cover, remove the toner cartridge, jam paper
at the paper outlet, insert paper from the manual feed slot, etc.
(4) Press the Cancel button to return to the printer to the initial state of the maintenance
mode.
■ Location of sensors
Develop release
sensor PCB ASSY
Top drive ASSY
Panel cable rack
Front cover sensor
Drum position sensor PCB ASSY
Sensors
External temperature/humidity sensor
External temperature/humidity sensor
Internal temperature sensor
Belt temperature sensor
(OK/NG of temperature/humidity)
°
XX
XX %/NG
°
XX
°
XX
Registration front sensor
Registration rear sensor
T1 paper edge sensor
Fig. 5-5
5-13
Sensing status
C/NG
C/NG
C/NG
High-voltage power supply
PCB ASSY
External temperature/humidity
sensor
T1 registration
front/rear sensor
PCB ASSY
PF ASSY
Confidential