ETA 251.626 Service Walkthrough
The 251.626 is often found in mid to high-end quartz chronographs on the market today.
ETA 251.262.pdf
It is a fairly complex quartz movement that has 5 motors, 2 with Red Coils, and 3 with Green Coils.
To begin the service we start by removing the 3 Indicator Maintaining Small Plates, and Date Indicator.
A 1.4mm screwdriver is all the is needed for every screw on the movement.
Here's a reference photo of the 3 screws for the Indic