In this condition I received the watch. It did not, the power reserve indicator signaled fully wound. The hand positioning worked. I bought it as "defective" and so it was - nothing stirred.
At the first look after opening the steel case back I noticed the lack of the spring on the capstone of the shock protection of the balance staff. Fortunately, however, the watch was glued and gummy that anyway hole and capstone were still present and did not tumble around somewhere in the movement.
In addition, the balance pivot was broken. Since the Junghans J80/12 has a special balance wheel in which the adjustment screws are recessed I could not use any balance of a replacement movement to a "normal" J80. Unfortunately, the replacement of a balance shaft exceeds my abilities by far. So the watch has to be brought to the watchmaker who changed the balance staff and even added a spring for the shock protection. Since I wanted to clean the watch myself I asked the watchmaker only to change the balance staff. So there was no test possible for an exact running of the watch...
When the watch was back with me I first relaxed the mainspring and already jumped the power reserve indicator to zero, so I was shure that this worked well.
After the disassembling of the winding rotor I could remove the entire winding group.
The dial made me most worried. The subsequently applied luminous material (at 3, 4, 5, 7, 11) of dots had been partially applied very bad from predecessors and I first decided to replace only the damaged and large dots. The luminous dots at 1, 2, 6, 8, 9, 10 seemed to me original but also partly not exactly round. Even the triangle under the 12 is original. But I will add some more informations to the luminous material again later.
To disassemble the movement, of course, the probably not original hands had to be taken off. They are too long, but appear from the period of the watch comes. Perhaps the former purchaser had the desire for longer hands. Who wants to see the correct length can see the watch with the right pointers here: Junghans J80/12; Junghans 680.75.
The luminous hands were evenly aged and I really wanted to keep them, but promptly crumbled radium from the hour hand when releasing the hand slightly.
Taking the movement out of the case and removing the dial one has a good view on the disk of the power reserve indicator.
The delicate balance staff is once assigned separately to the side. Gradually, the mechanics of the power reserve comes with the differential gear to days.
The main spring in the barrel is clearly dirty and has a slight bend but I have this again installed (and easily bent into shape).
After cleaning: The whole stone is back in stock, the capstone shown here I had again given a new oil droplets as the drop is not sitting perfectly in the middle...
Now it was time again to deal with the dial (only with mask!). At first I tried to reduce the later attached luminous dots. They looked like melted.
A few have completely fallen off.
These I have tried to replace. Here the first layer, the paste dries quickly and then reduced significantly. Therefore, some layers have to be applied. Since I have ventured this the first time I have several attempts needed.
Even with the hands I initially tried to replace only the fallen off pieces. In the first photo the freshly applied paste can be seen; in the second picture after drying of the last layer. The third photo shows the front of the hand. However, overall I was dissatisfied with the luminous dots. Finally, I have all removed (except for the central triangle of the 12) and as best I could, be renewed. And in the last end also the luminous of the hands...
Here the final result.
What has always fascinated me in the revision of the caliber is the height of the movement.
After all seven millimeters!
Who needs more details to the caliber Junghans J80/12: Junghans J80/12 ; Junghans 680.75