Panasonic UF-490 Service Manual page 75

4.3.6. Information Code: 434
START
Is communication with the
reference unit successful?
Does the trouble occur
regardless of the remote unit?
The telephone line may have
a high level of white noise
and/or frequent impulse noise.
Ask the telephone company
to check the line.
No
Yes
No
Yes
END
Replace the SC PCB.
Can the transmitter in
question transmit to the
other units?
No
Change the parameter in Service Mode 1.
(Refer to Sect. 5.1.2.)
for transmitter: #010: Increase Tx Level
for receiver : #011: Reduce Rx Sensitivity Level
75
Check the remote unit in
Yes
question.
(Remote unit is defective)