Brother HL-3040CN Service Manual page 367

LCD
TMP External temperature sensor
HUM External humidity sensor
MAC Internal temperature sensor
BT Belt thermistor
Note:
If the sensor detects the abnormal value, the machine displays "NG" on the LCD.
(3) Change the detecting conditions to check that the indication on the LCD changes
according to the sensor state. For instance, insert paper through the registration front/
rear sensor, open the top cover or the back cover, remove the toner cartridge, jam paper
at the paper outlet and insert paper from the manual feed slot, etc.
(4) Press the Cancel button to return the machine to the initial state of the maintenance
mode.
Sensors
7-13
Sensing status
(OK/NG of temperature/humidity)
XX C/NG
XX%/NG
XX C/NG
XX C/NG
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