What to check

With the telephone cover removed listen for the hum at the handset earphone and then disconnect the wire connected to the 'P' terminal. If the hum stops this indicates the microphone has failed or is failing.

Corrective Action

Replace the microphone or the handset. Identify the model of the telephone using the links below.

Additional notes

Note: We differentiate between the terms 'telephone' and 'handset'.

Links

https://www.entryphone.co.uk/shop/productdetail/200-HS