A watch that is stopped: Where to begin

Always assume the battery.

It is the easiest thing to repair and even when the customer “Knows it is new / full and it is something else”, check it. It isn’t wasted time.

Even when I know the battery is full because I have put it in there
I still check the battery.

A few times I have come across a new battery that is dead or other times I have stupidly refitted the old dead battery (usually happens in a busy patch and you loose time for nothing when you can least afford it).

How to test a watch battery properly

Now you begin the troubleshooting process