TOSHIBA SG1801
Instrukcja Serwisowa

4. Cannot make a phone call (pulse).
NG Can the base and handset be connected? OK Check whether T/P SW is PULSE. OK While in TALK MODE, press dial key of the handset. Check whether the square waveform from Pin 55 of IC4 is fed. OK Check Q2, RL1, R20,R43, R95, D19 and their peripheral circuits. NG Check IC4 and R95. NG Set T/P SW to PULSE. See 3. The base and handset cannot be connected.

5. Cannot make a phone call (tone).
NG Can the base and handset be connected? OK Check whether T/P SW is TONE. OK While in TALK MODE, press dial key of the handset. Check whether the tone wave output from pin 24 and Pin 25 of IC3 is fed. OK Can tone signal be heard from the handset speaker? OK Check the base TEL-line circuit and RELAY control circuit.
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See 3. The base and handset cannot be connected.

NG Set T/P SW to TONE.

NG

Check IC3 and its peripheral circuit.

NG

Check R18, R37,R33, R133 and their peripheral circuits.