Panasonic KX-F900 Service Manual page 70

i
KX-F900
(1) Defective ITS (Integrated telephone system) section
€_) No speakerphone transmission/reception
Following the ITS section or NCU section, search for the route between the microphone and
the telephone line (sending) or between the telephone line and the speaker (receiving) where the signal disappears.
Check the components at that point.
_) No pulse dialing
I
Does the voltage at 3 pin of
IC151 change between high
level and low level?
I YES
Check the pulse dial circuit.
I NO
I
Replace PC102. I
, r
Does the voltage at 3 pin of IYES I
IC151 change between high
level and low level?
I
,I
Replace PC102 or R281.
Check IC151.
(_) No ring tone
L Check the Bell detection
circuit.
1
Is the Bell detection circuit
OK?
YES
/
Does a ring tone I,,^
signal appear at 44
pins of IC11 (digital
board)?
YES
Replace IC11.
Following the ITS section and search
for the point on the route between
the modem and the speaker where
the signal disappears.
Check the components at that point.
(_ No tone dialing
Does a DTMF signal appear
at 44 pins of ICll (digital
board)?
YES
Following the NCU section and ITS section
and search for the point on the route between
44 pins of IC11 and the telephone jack.
Where the signal disappears.
Check the components at that point.
Replace IC11.
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