4. Cannot make a phone call (pulse).
Can the base and handset be connected? OK While in TALK MODE, press NG dial key of the handset. Check whether square waveform from pin 13 of IC11 is fed. OK Check Q17, RL1 and their peripheral circuits. NG See 3. The base and handset cannot be connected.
Check IC11.
5. Cannot make a phone call (tone).
Can the base and handset be connected? OK While in TALK MODE, press dial key of the handset. Can tone waveform from Pin 1 of IC11 is fed? OK Can tone signal be heard from the handset speaker? OK Check the base TEL-line circuit and RELAY control circuit. NG Check IC4, Q3 and their peripheral circuits. NG NG See 3. The base and handset be cannot be connected.
