Battery Change on a 1 piece case
So you have found a watch with no watch back. The first question that will pop into your mind is how to open it to change the battery. This you will find out a bit later on. First I will point out a few things you should know first.
Generally watches with a 1 piece casing are gold watches. The reason they choose to make the watch this way is it has better water resitancey simply because their is no back.
Secondly you are going to remove the glass and all of the movement from the casing so you need a clean tidy desck to work on.
Thirdly there is an inherrent risk of breaking the glass or stem you can not help this, it is down to the design of the watch.
Here is the watch for the battery to be fitted. I have asked the customer for 1 hour to do this job. Not because it will take this long but incase i have a problem with the stem or glass. I have also found out that the watch has been stopped for more than 6 months so there maybe problems with battery acid but the watch has no sign of water damage on the face so hopefully the stem is not rusty.
The back of the watch has a lip that looks like watch back but do not be fooled. Many times you will see where people have tried to prise the back off and marked the case. If you are unsure look with a high power eyeglass.
To start you will need to remove the crown (except on a few old Seiko models where there is a button under the glass). Usually the crown is forced off carefully with the tweesers but occasionally there is a screw or tiny back to release the stem
Here you can see the stem. It is called a female 2 part stem and it is designed especially for this type of watch. On very cheaply made it can be a normal stem which means you are forcing the stem from the bolt and with it possible problems with the setting mechanism.
Now you need to remove the glass. there are 2 ways to do this. Either with the glass claws or with air. I prefer to use air as there is less chance of damaging the glass. Place Rodico or Blue Tac around the pendent to act as a seal. Cup the watch in your hand so that nothing can fall out of the watch and pump air into the watch with a 20ml syringe untill the glass pops off.
Here you see the glass has come off perfectly with no marks on it.
Remove the movement and place it in a movement holder. Sometimes you need to push the winder into the run position with a screwdriver. Occasionally there is a ring holding the movement that needs to be removed.
On removal of the battery I discovered the battery acid I expected. This is very common on these watches as most people only use them occasionally. note: try not to mark/fold the plastic insulator like i did in this watch. aesthetically it is not good .
With the contact now clean I can fit a new battery. When you removed the stem you will have left the watch in the time changing position so press the stem into the run position to see if the watch is working. And it does.
Refit the movement and any packing ring so the stem lines up with the pendent.
To refit the stem is the only bit that can be tricky. You need to align the 2 parts up before pushing them untill they click together.
refit the glass with the glass claws, by hand or with the press and you have a working watch.