Toshiba FT-7800A Service Manual page 16

4. Cannot make a phone call (pulse).
Preset: Press "FLASH" key for about 2 seconds, then press "#" key to enter "Pulse" mode.
Can the base and handset
be connected?
OK
While in TALK MODE,
press number key of the
handset.
Check whether square
waveform from pin 13 of
IC2 is fed.
OK
Check Q16, RL1 and their
peripheral circuits.
5. Cannot make a phone call (tone).
Preset: Press "FLASH" key for 2 seconds, then press """ key to enter "Tone" mode.
Can the base and handset
be connected?
OK
While in TALK MODE,
press dial key of the
handset. Can tone
waveform from pin 1of IC2
is fed?
OK
Can tone signal be heard
from the handset speaker?
OK
Check the base TEL-line
circuit and RELAY control
circuit.
See 3. The base and
NG
handset cannot be
connected.
NG
Check IC2.
NG
See 3. The base and
handset be cannot be
connected.
NG
Check IC2.
NG
Check IC1, Q3 and their
peripheral circuits.
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