Brother MFC-9420CN Service Manual

Confidential
9-58
[ 6 ] Troubleshooting of the control panel
L-1
Nothing is displayed on the LCD.
User Check
(1) Verify if the power switch is turned off.
Possible cause Step Check Result Remedy
Connection
between main
PCB and control
panel PCB
1 Main PCB and
control panel PCB
are properly
connected
No Fix the connector properly.
Harness between
main PCB and
control panel
PCB
2 Harness is damaged. Yes Replace the harness with a normal
part.
Connection
between main
PCB and low-
voltage power
supply PCB
3 Main PCB and low-
voltage power supply
PCB are properly
connected.
No Fix the connection properly.
Harness between
main PCB and
low-voltage
power supply
PCB LCD
4 Harness is damaged. Yes Replace the harness with a normal
part.
LCD 5 Replacement of LCD
solves the problem.
Yes Replace the LCD with a normal
part.
Control panel
PCB
6 Replacement of
control panel PCB
solves the problem.
Yes Replace the control panel PCB
with a normal part.
Low-voltage
power supply
PCB
7 Replacement of low-
voltage power supply
PCB solves the
problem.
Yes Replace the low-voltage power
supply PCB with a normal part.
Main PCB 8 Replacement of main
PCB solves the
problem.
Yes Replace the main PCB with a
normal part.

Brother MFC-9420CN Specifications

General

Print technology	Laser
Maximum resolution	1200 x 2400 DPI
Economical printing	Yes
Print speed (black, normal quality, A4/US Letter)	31 ppm
Print speed (color, normal quality, A4/US Letter)	8 ppm
Digital sender	No
Number of print cartridges	4
Scanner type	Flatbed scanner
Scanner features	Scan to: e-mail, image, OCR, file
Copier resize	25 - 400 %
Maximum copy resolution	600 x 600 DPI
Maximum number of copies	99 copies
Copy speed (black, normal quality, A4)	31 cpm
Copy speed (color, normal quality, A4)	8 cpm
Faxing	Color faxing
Fax memory	500 pages
Modem speed	33.6 Kbit/s
Fax speed dialing (max numbers)	200
Total input capacity	750 sheets
Maximum input capacity	250 sheets
Auto document feeder (ADF) input capacity	35 sheets
Maximum internal memory	576 MB
Bundled software	ScanSoft PaperPort Presto! PageManager
I/O ports	IEEE-1284 USB 2.0
Dimensions (WxDxH)	483.5 x 514 x 530 mm
Printer management	BRAdmin Professional, MIB-II
Networking features	10Base-T/100Base-TX
All-in-one functions	Fax, Scan
Color all-in-one functions	copy, fax, print, scan
Compatible operating systems	Windows 98(SE)/ Me/ NT WorkStation 4.0/ 2000 Professional/ XP Mac OS 9.1 - 9.2, Mac OS X 10.2.4+
Sustainability certificates	ENERGY STAR
Power consumption (standby)	85 W
Power consumption (PowerSave)	16 W
Power consumption (average operating)	1090 W
Operating temperature (T-T)	10 - 32 °C
Operating relative humidity (H-H)	20 - 80 %
Market positioning	Business