Brother MFC-9420CN Service Manual page 286

L-2
The control panel does not work.
User Check
(1) No
Possible cause Step
Key sticking 1
Connection 2
between main
PCB and control
panel PCB
Harness between 3
main PCB and
control panel
PCB
Rubber key 4
Control panel 5
PCB
Main PCB 6
L-3
Printing from Macintosh applications fails.
User Check
(1) Verify that the printer driver supplied with the machine has been installed in the system
folder and selected in the selector.
(2) Check the port selected in the selector. The selected port has to match the actual port to
which the printer cable is connected.
Possible cause Step
Fault in machine 1
Breakage of main 2
PCB
Check
Any key on control
panel is stuck.
Main PCB and
control panel PCB
are properly
connected.
Harness is damaged.
Replacement of
rubber key solves the
problem
Replacement of
control panel PCB
solves the problem.
Replacement of main
PCB solves the
problem.
Check
Test page can be
printed using the
method described in
8.4.5 'Test Pattern 1'
in Chapter 8.
Printing can be made
using an appropriate
PC, printer cable,
and RS-100M?
9 - 5 9
manuals4you.com manuals4you.com
Result Remedy
Yes Clean up the panel cover, or
remove the burrs from panel
cover and panel keys.
No Fix the connection properly.
Yes Replace the harness with a normal
part.
Yes Replace the rubber key with a
normal part.
Yes Replace the control panel PCB
with a normal part.
Yes Replace the main PCB with a
normal part.
Result Remedy
No Check the symptom of the
problem and refer to an
appropriate section in this Chapter
to solve the problem.
No Replace the main PCB.
Confidential