■ No ringing sound.
Step
Cause
Ring delay
1
Ring volume
2
Connection
between main
3
PCB and NCU
PCB
Speaker
4
NCU PCB
5
Main PCB
6
Check
Ring delay is set to "0".
Ring volume is set to
"OFF".
Are the main PCB and
NCU PCB connected
correctly?
Is the problem solved
after replacing the
speaker?
Is the problem solved
after replacing the NCU
PCB ASSY?
Is the problem solved
after replacing the main
PCB ASSY?
1-55
Result
Remedy
Change the ring delay
Yes
settings to another value.
Change the ring volume
Yes
setting to another value.
Reconnect the connector.
No
Replace the Speaker.
Yes
Replace the NCU PCB
Yes
ASSY.
Replace the main PCB
Yes
ASSY.
Confidential