I took my electronic Hammy in for a battery change ( because they are better at it than me) and it proved far from simple. It took two tiny screws to remove the battery cover and then when the battery had been replaced it fired up....and stopped. The Watchmaker then disappeared and came back with a handful of tools , oil, and some blue tack. He oiled the necessary parts, went over the innards and all systems ar go.
The cost of this.....5.98 
So the Hammy is going to get a few days wrist time, I have to look after it for Steve 
D C Watchmakers.
Support your Independant folks.
Originally from RLT . Thanks Roy.
Cheers