Brother International DCP 8040 Service Manual - Page 236

Main PCB, relay PCB,

Page 236 highlights

MFC-8440/8840D/8840DN, DCP-8040/8045D/8045DN SERVICE MANUAL F-5 Speaker is silent during on-hook dialing. Possible cause Connection between main PCB and speaker Speaker Connection between main PCB and NCU PCB Harness between main PCB and NCU PCB Connection between main PCB, relay PCB, and control panel PCB Harness between main PCB, relay PCB, and control panel PCB NCU PCB Relay PCB Main PCB Step 1 2 3 4 5 6 7 8 9 Check Main PCB and speaker are properly connected. Replacement of speaker solves the problem. Main PCB and NCU PCB are properly connected. Harness wire is damaged. Main PCB, relay PCB, and control panel PCB are properly connected. Harness wire is damaged. Replacement of NCU PCB solves the problem. Replacement of relay PCB solves the problem. Replacement of main PCB solves the problem. Result Remedy No Fix the connection properly. Yes Replace the speaker with a normal part. 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 NCU PCB with a normal part. Yes Replace the relay PCB with a normal part. Yes Replace the main PCB with a normal part. F-6 Dialing function does not switch between "tone" and "pulse". Possible cause Connection between main PCB and NCU PCB Harness between main PCB and NCU PCB NCU PCB Main PCB Step 1 2 3 4 Check Main PCB and NCU PCB are properly connected. Harness wire is damaged. Replacement of NCU PCB solves the problem. Replacement of main PCB solves the problem. Result Remedy No Fix the connection properly. Yes Replace the harness with a normal part. Yes Replace the NCU PCB with a normal part. Yes Replace the main PCB with a normal part. 6-33

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MFC-8440/8840D/8840DN, DCP-8040/8045D/8045DN
SERVICE MANUAL
6-33
F-5
Speaker is silent during on-hook dialing.
Possible cause
Step
Check
Result
Remedy
Connection
between main
PCB and
speaker
1
Main PCB and speaker are
properly connected.
No
Fix the connection properly.
Speaker
2
Replacement of speaker
solves the problem.
Yes
Replace the speaker with a
normal part.
Connection
between main
PCB and NCU
PCB
3
Main PCB and NCU PCB are
properly connected.
No
Fix the connection properly.
Harness
between main
PCB and NCU
PCB
4
Harness wire is damaged.
Yes
Replace the harness with a
normal part.
Connection
between main
PCB, relay PCB,
and control
panel PCB
5
Main PCB, relay PCB, and
control panel PCB are
properly connected.
No
Fix the connection properly.
Harness
between main
PCB, relay PCB,
and control
panel PCB
6
Harness wire is damaged.
Yes
Replace the harness with a
normal part.
NCU PCB
7
Replacement of NCU PCB
solves the problem.
Yes
Replace the NCU PCB with
a normal part.
Relay PCB
8
Replacement of relay PCB
solves the problem.
Yes
Replace the relay PCB with a
normal part.
Main PCB
9
Replacement of main PCB
solves the problem.
Yes
Replace the main PCB with
a normal part.
F-6
Dialing function does not switch between "tone" and "pulse".
Possible cause
Step
Check
Result
Remedy
Connection
between main
PCB and NCU
PCB
1
Main PCB and NCU PCB are
properly connected.
No
Fix the connection properly.
Harness
between main
PCB and NCU
PCB
2
Harness wire is damaged.
Yes
Replace the harness with a
normal part.
NCU PCB
3
Replacement of NCU PCB
solves the problem.
Yes
Replace the NCU PCB with
a normal part.
Main PCB
4
Replacement of main PCB
solves the problem.
Yes
Replace the main PCB with
a normal part.