It looks like there is no supply to the bell box or the SCB unit has failed(anti tamper unit in bell box). Check the fuses inside the panel (should be marked bell and battery) if these are OK the chances are the SCB has failed. It is probably cheaper to replace the complete bell box, if the battery is more than three years old change that as well. Just make a sketch of what wires go where before you disconnect them.
To stop noise in bell box remove cover and disconnect or snip one off the wires going to speaker or sounder
Jackieboy
February 2007