I took yesterday 8 dead G-Shock's to school, to change a battery in some lost moments. Today there were more experiments, but I thought there would be some lost moments too. I found 11 dead or near dead G-Shock's yesterday evening.
It took me 5 hours to change them all. The DWX model was the most tricky. The DW-8300 and DW-8140 were the easiest.
Here they are all set to the DCF77.5
As a bonus, there was a class in a classroom, where I needed to set up an experiment for the next hour with very enthousiastic pupils, who everytime yelled "Hi Sjors". After a few times, I thought I should film this