Toshiba FT-8800 Service Manual page 18

7. The voice of the caller cannot be heard (incoming call).
Can the base and handset be
connected?
OK
The 1 kHz, 77.5mV sine
waveform is applied to TEL-
line of the base, can the 1 kHz
sine waveform from the Q3
collector be fed?
OK
Check whether there is the
1 kHz sine wavefor m at
pin 24 of IC1.
OK
Check whether there is the
1 kHz sine wavefor m at
pin 20 of IC1.
OK
Check whether there is the
1 kHz sine waveform at C80.
OK
TX output signal from the
base is detected by the liner
detector, can the 1 kHz sine
waveform be fed?
OK
Check whether there is the
1 kHz sine waveform at pin 9
of IC606 on the handset unit.
OK
Check whether there is the
1 kHz sine waveform at pin 3
of IC601.
OK
Check whether there is the
1 kHz sine waveform at the
pin 18 of IC601.
OK
Check whether there is the
1 kHz sine waveform at R678
or R708.
OK
Check SP801 and WA801,
WA802.
NG See 3. The base and handset
cannot be connected.
Check the base TEL-line
NG
circuit and REPLAY control
circuit.
NG Check Q4 and its peripheral
circuit.
NG Check C1 and its peripheral
circuit.
NG Check RT3 and its
peripheral circuit.
NG
Check base RF unit.
NG Check handset RF unit and
the peripheral circuit of IC606.
NG Check RT602, Q601 and
their peripheral circuits.
NG Check IC601 and its
peripheral circuit.
Check Q602, Q603 and its
NG
peripheral circuit.
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