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 22 of IC5 is fed. OK Check Q10, RL1 and their peripheral circuits. NG See 3. The base and handset cannot be connected.
Check IC5.
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 20 of IC8 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 IC1, Q3 and their peripheral circuits. NG NG See 3. The base and handset be cannot be connected.
