Toshiba FT-8981, Service Manual

Page: 19 / 52

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7. The voice of the caller cannot be heard (incoming call).
Can the base and handset be
connected? See 3. The base and handset
cannot be connected.
OK
NG
The 1 kHz, -15dBm sine
waveform is applied to TEL-
line of the base, can the 1 kHz
sine waveform from the Q3
collector be fed? Check the base TEL-line
circuit and REPLAY control
circuit.
NG
Check whether there is the
1 kHz sine wavefor m at
pin 24 of IC1. Check Q11 and its peripheral
circuit. NG
OK
OK
Check whether there is the
1 kHz sine wavefor m at
pin 20 of IC1. Check IC1 and its peripheral
circuit. NG
OK
TX output signal from the
base is detected by the liner
detector, can the 1 kHz sine
waveform be fed?
Check base RF unit.
NG
OK
Check whether there is the
1 kHz sine waveform at pin 9
of IC606 on the handset unit. Check IC606, Q612 and
their peripheral circuit. NG
OK
Check whether there is the
1 kHz sine waveform at pin 3
of IC601. Check RT602, Q601 and
their peripheral circuits. NG
OK
Check whether there is the
1 kHz sine waveform at the
pin 18 of IC601. Check IC601 and its
peripheral circuit. NG
OK
Check whether there is the
1 kHz sine waveform at pin
1, 2 of SP801. Check Q602, Q603 and their
peripheral circuit.
NG
OK
Check SP801 and W801,
W802.
Check handset RF unit.
NG
OK
Check whether there is the
1 kHz sine wavefor m at
C52. Check RT3 and its
peripheral circuit. NG
OK