Troubleshooting Of Fax Functions - Brother MFC8420 Service Manual

CHAPTER 6 TROUBLESHOOTING
7.

TROUBLESHOOTING OF FAX FUNCTIONS

FAX can't send it.
F-1
User Check
(1) Verify that the telephone cord is securely inserted.
Possible cause
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
Connection of
FPC key
FPC key
NCU PCB
Control panel
PCB
Main PCB
Step Check
Dialing signal (PB or DP)
1
comes out normally in each
mode.
(Use telephone line emulator.)
Main PCB and NCU PCB are
2
properly connected.
Harness wire is damaged.
3
Main PCB and control panel
4
PCB are properly connected.
Harness wire is damaged.
5
FPC key is properly
6
connected.
Replacement of FPC key
7
solves the problem.
Replacement of NCU PCB
8
solves the problem.
Replacement of control panel
9
PCB solves the problem.
Replacement of main PCB
10
solves the problem.
Result
Yes
No
Yes
No
Yes
No
Yes
Yes
Yes
Yes
6-30
Remedy
Check the dialing mode
setting at customer's again.
Check the telephone line
cord between machine and
socket.
Fix the connection properly.
Replace the harness with a
normal part.
Fix the connection properly.
Replace the harness with a
normal part.
Fix the connection properly.
Replace the FPC key with a
normal part.
Replace the NCU PCB with
a normal part.
Replace the control panel
PCB with a normal part.
Replace the main PCB with
a normal part.