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■ Speaker is silent during on-hook dialing.
■ Dialing function does not switch between "tone" and "pulse".
Step Possible cause Check
Result
Remedy
1
Connection
between main
PCB and
speaker
Are the main PCB and
speaker connected
properly?
No
Reconnect the connector
properly.
2
Speaker Is the problem solved
after replacing the
speaker?
Yes
Replace the Speaker.
3
Connection
between main
PCB and NCU
PCB
Are the main PCB and
NCU PCB connected
properly?
No
Reconnect the connector
properly.
4
Harness
between main
PCB and NCU
PCB
Is the harness
damaged?
Yes
Replace the harness with a
normal one.
5
Connection
between main
PCB and control
panel PCB
Are the main PCB and
control panel PCB
connected properly?
No
Reconnect the connector
properly.
6
Harness
between main
PCB and control
panel PCB
Is the harness
damaged?
Yes
Replace the harness with a
normal one.
7
NCU PCB Is the problem solved
after replacing the NCU
PCB ASSY?
Yes
Replace the NCU PCB
ASSY.
8
Main PCB Is the problem solved
after replacing the main
PCB ASSY?
Yes
Replace the main PCB
ASSY.
Step Possible cause Check
Result
Remedy
1
Connection
between main
PCB and NCU
PCB
Are the main PCB and
NCU PCB connected
properly?
No
Reconnect the connector
properly.
2
Harness
between main
PCB and NCU
PCB
Is the harness
damaged?
Yes
Replace the harness with a
normal one.
3
NCU PCB Is the problem solved
after replacing the NCU
PCB ASSY?
Yes
Replace the NCU PCB
ASSY.
4
Main PCB Is the problem solved
after replacing the main
PCB ASSY?
Yes
Replace the main PCB
ASSY.