Chapter Iv Troubleshooting; Inspection Mode - Brother HL-720 - B/W Laser Printer Service Manual

CHAPTER IV TROUBLESHOOTING

1.

INSPECTION MODE

1.1 Inbuilt Inspection Modes
The printer incorporates the following inspection modes such as the factory inspection
mode and the test print mode.
Factory inspection mode, Continuous grid pattern print mode, 3 patterns print mode, NV-
RAM value dump mode, ROM code update (FLASH rom only), RAM check and 4% density
test print..
The operation of the inspection mode is as follows.
(1) Turn off the power to the printer.
(2) With the top cover open, turn on the power while holding down the button
on the operation panel.
When entering this mode, the DRUM LED is ON. Holding down the button causes
the LEDs to turn ON in the order DRUM -> ALARM -> READY -> DATA -> DRUM.
When you release the button, a mode is selected. The mode selected is indicated by
the LED which is ON when you release the button. The inspection modes are
assigned to the respective LEDs as shown below.
LED
DRUM
ALARM
READY
DATA
DRUM + ALARM
ALARM + READY
READY + DATA
Details of the factory inspection mode are as follows.
This mode is used to check if the sensors in the printer function correctly. In the process of
this inspection, the LEDs and buttons are also checked. On entering this mode, the LEDs
show the status of the respective sensors as follows.
Type of inspection
Factory inspection mode
Continuous grid pattern print mode
3 patterns print mode (grid horizontal
lines and black)
NV-RAM value dump mode
The ROM code update (only when
flash memory is mounted)
RAM check
4% density printing
IV-1