Squawking Reson8 bell box

[Icanfixit]

I have a Reson8 bell box which has started to make a noise like an hysterical duck. It happens randomly and is getting more frequent. Going into Engineer mode doesn't stop it but running a few tests does. I ran a strobe test today and have left it in Strobe Test Off mode to stop the noise. I've tested the siren/bell which is fine and it sets/unsets/activates an alarm in perfect order. I can't see it being a power/battery problem as nothing would work properly when activated/tested.
I took the cover off to have a quick look but the tamper fault certainly worked and it's hard being that close to the siren going off. I didn't find a duck!
Any ideas?

 

[Handymanjo]

Sounds like bell box is faulty ?
I would replace asap before bell box cause you a problem in the early hours.
Could be water damaged from the heavy rain a few weeks ago and now causing it to squawk.

 

[sparkymarka]

Have know the ag6 bellbox ( also Honeywell ) make this noise when the internal bell box battery is faulty