Brother MFC-8460N Service Manual page 383

(F-2) Speed dialing and One-touch dialing can't be used.
Possible cause
Speed dialing,
One-touch dialing
Dialing mode
setting
Connection
between main
PCB and NCU
PCB
Harness between
main PCB and
NCU PCB
Connection
between main
PCB and control
panel PCB
Harness between
main PCB and
control panel PCB
Rubber key
NCU PCB
Control panel PCB
Check
Step
1 A fax transmission can
be made using the key,
ten?
2 Dialing signal (PB or
DP) comes out normally
in each mode.
(Use telephone line
emulator.)
3 Main PCB and NCU
PCB are properly
connected.
4 Harness is damaged.
5 Main PCB and control
panel PCB are properly
connected.
6 Harness is damaged.
7 Replacement of rubber
key solves the problem.
8 Replacement of NCU
PCB solves the problem.
9 Replacement of control
panel PCB solves the
problem.
Result
Yes Replace the main PCB.
Yes Check the dialing mode setting
at customer's again.
Check the telephone line cord
between machine and socket.
No Fix the connection properly.
Yes Replace the harness with a
normal part.
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 NCU PCB with a
normal part.
Yes Replace the control panel PCB
with a normal part.
9-60
Remedy
Confidential