What to check

Test the door panel loudspeaker. A simple method is to briefly link a wire from the 12v AC (found at the common connection to the call buttons) and the 'E' terminal on the amplifier. If the speaker is working it will emit a loud buzz.

Alternatively - disconnect the speaker from the circuit board and measure the resistance across wires. The reading should be either 8 or 45 ohms (check the impedance value printed on the speaker). A closed or open circuit reading indicates the speaker has failed.

Corrective Action

Replace the speaker.

Additional notes

Identify replacement part from the links below.

Links

https://www.entryphone.co.uk/shop/productdetail/92-LS70

https://www.entryphone.co.uk/shop/productdetail/10-LS70

https://www.entryphone.co.uk/shop/productdetail/65AMP_LS