Hi, I have an old acet door entry system, buzzer and handset for 3 flats, not sure what model pic attached.

 

One of the flats says he gets a whining noise some nights, and goes to the box and hears a whine from that too.

Ive just had a fire alarm fitted, but I think he had it before that ?

 

Can anyone please help ?

thanks

Mic levels too high and feedback. Plus is the on hook switch broke / need adjusting? 

Thanks Ill check that

Also check that all handsets are seated correctly, feedback is often caused if someone hasnt replaced their handset properly 

Thanks for your help Peter will do

I checked but cant see any volume adjustment on the mic.

So I guess the problem is the handset, not gained access to check that yet. 

29 minutes ago, nwpattesting said:

I checked but cant see any volume adjustment on the mic.

where did you look?

32 minutes ago, nwpattesting said:

I checked but cant see any volume adjustment on the mic.

So I guess the problem is the handset, not gained access to check that yet. 

Normally two pots I thought

As it’s happening at night, I wonder if one of the users is leaving the handset off the hook (thinking it won’t disturb them)? If they leave it flat in a surface you are likely to get feedback from that.