Scantronic 9750 showing 'blocks' instead of usual display

[Baneybo]

Our 9750 control unit's display is showing 8 squares instead of its usual display (date and time I think). There's no fault (red spanner) light showing.
Is it stuffed? I'm a bit apprehensive about trying to input the user or engineer codes in case the alarm goes of.
Any help would be much appreciated!

 

[sparkymarka]

How old is battery ? Have you had any work done in the house ? Lost data or clock wire ...Down power sytem is probably your only option , it may come back to normal

 

[musszzy]

Yes switch off then on. Works for nuclear submarines..... Apparently