Brother MFC8440D Service Manual page 235

7/13/2019
CHAPTER 6 TROUBLESHOOTING
F-4 No bell ring.
Possible cause
Ring delay
Ring volume
Connection
between main
PCB and NCU
PCB
Harness
between main
PCB and NCU
PCB
Speaker
Relay PCB
NCU PCB
Main PCB
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Step Check
Ring delay is set to "0".
1
Ring volume is set to "OFF".
2
Main PCB and NCU PCB are
3
properly connected.
Harness wire is damaged.
4
Replacement of speaker
5
solves the problem.
Replacement of relay PCB
6
solves the problem.
Replacement of NCU PCB
7
solves the problem.
Replacement of main PCB
8
solves the problem.
Brother 8840D Service Manual
Result
Yes Set the ring delay to other
than "0".
Yes Set the ring volume to other
than "OFF".
No Fix the connection properly.
Yes Replace the harness with a
normal part.
Yes Replace the speaker with a
normal part.
Yes Replace the relay PCB with a
normal part.
Yes Replace the NCU PCB with
a normal part.
Yes Replace the main PCB with
a normal part.
6-32
Remedy
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