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KX-F680BX/KX-F2681BX
(1) Defective ITS (Integrated telephone system) section
@
No handset and speakerphone transmission/reception
Following the ITS section or NCU section, search for the route between the handset microphone and the telephone
line (sending), or between the telephone line and the handset speaker (receiving), or 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.
Does the voltage at 2 pin of
IC151 change between high
level and low level?
Check the pulse dial circuit.
Replace PC102.
Does the voltage at 2 pin of
IC151 change between high
level and low level?
Replace PC102 or R281.
Check IC151.
Check the Bell detection
circuit.
Is the Bell detection circuit
OK?
Does a ring tone
signal appear at
28,29 pins of IC5
(digital board) ?
Replace IC5.
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.
YES
YES
YES
NO
Does a DTMF signal appear
at 28,29 pins of IC5 (digital
board) ?
Replace IC5.
Following the NCU section and ITS section
and search for the point on the route between
28,29 pins of IC5 and the telephone jack.
Where the signal disappears.
Check the components at that point.
YES
NO
YES
NO
C
No tone dialing
A
No pulse dialing
B
No ring tone
NO
NO
Summary of Contents for KX-F680BX
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Page 130: ... 165 KX F680BX KX F2681BX EC1 EC2 EC3 EC4 EC5 EC6 EC7 EC9 EC10 EC11 EC12 EC13 EC8 TOOLS ...
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