No sound from external bell box

Hi guys

I expect this may be a basic question however it has come to my attention that the sounder is no longer working on the DIY install I did 8 years ago when I moved in. There is still some light from the strobe when the alarm is triggered however no evident sound. It's an ADE Reson 8. I presume the cable is in tact between the control panel and bell box as it recognises an alarm event. As I have not touched the bell box since installing it 8 years ago, is it likely to just be a new battery required within the bell box, or would the sounder still work ok off the mains even if the battery is now dead?

Before I go up and fix I just want to have an idea whether a simple battery replacement will suffice or a full replacement of the bell box unit?

I would appreciate any thoughts regarding this.

Thanks in advance

Rick

One of a couple of things , the piezo is knackered or the trigger wire for the bell is cut/ corroded , or water damaged bell pcb
Best way to test if you don't have a multimeter swop the strobe and the bell trip around in the panel if the strobe still flashes it's not the cable

Thanks for the advice. So i ordered a new bell box and battery and after replacing the new battery within the main alarm unit my external sounder started working within the old bell box? Surely the sound should also work off the mains supply alone and hence get sound form the bell box even when the battery is flat? Any thoughts or guidance would be appreciated?

Thanks in advance.
Rick

Have you checked the bell box for water damage/ Corroded wires ?