Step by step guide to changing batteries on
Tactic 371+,5xx+, IHT-Digi+, SB-Digi+, Talento 3xx+,4xx+,7xx+
   

1,
Locate Lever point

 

2,
Gently lever timer module from assembly with small flat bladed tool

 

3,
Remove timer module taking care not to stress ribbon cable
4,
Remove CR2032 cell from assembly and fit new button cell
To reassemble reverse the above process.