Read Panasonic KX-AT7730RU Service Manual online
20
KX-AT7730 Series
7.4.
TONE DIAL TORUBLE
7.5.
THE ELECTRONIC VOLUME OF THE SPEAKER-PHONE DOES NOT
WORK
WORK
7.6.
THE ELECTRONIC VOLUME OF HANDSET DOES NOT WORK
Does a DTMF tone sound?
Yes
No
Yes
Check Pin60 and Pin61 of IC1,
R123, R124.
R123, R124.
Yes
Does the DTMF tone mix
two-frequencies?
two-frequencies?
Does a DTMF signal appear
at Pin9 of IC5?
at Pin9 of IC5?
Yes
Does a DTMF signal appear
at Pin49 and Pin50 of IC1?
at Pin49 and Pin50 of IC1?
Check Q3 and R81, C81.
No
No
No
Check IC5, R82.
Check IC1.
Press the speaker-phone button and create a
dial tone.
dial tone.
No
Check Q15, Q16 and R67-R70
and pin56-59 of IC1.
and pin56-59 of IC1.
Yes
Does the volume change with the press of
Navigation key?
Navigation key?
OK
Lift the handset and create a dial tone.
No
Yes
Does the volume change with the press of
Navigation key?
Navigation key?
OK
Check Q11, R37 and pin56, 57 of IC1.
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