Revision of a Junghans J80/12; Junghans 680.75

A movement as high as a sandwich


Junghans J80/12; Junghans 680.75; Front; found condition


Junghans J80/12; Junghans 680.75; Front; found condition

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.


Junghans J80/12; 680.75; movement


Junghans J80/12; 680.75; movement

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.

Broken balance pivot!


Junghans J80/12; 680.75; balance wheel

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...


Junghans J80/12; Junghans 680.75; Front

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.


Junghans J80/12; 680.75; Rotor


Junghans J80/12; 680.75; Detail


Junghans J80/12; 680.75; Detail

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.


Junghans J80/12; 680.75; removal of the hands


Junghans J80/12; 680.75; dial

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.


Junghans J80/12; 680.75; Detail


Junghans J80/12; 680.75; Detail


Junghans J80/12; 680.75; power reserve indicator disc

Taking the movement out of the case and removing the dial one has a good view on the disk of the power reserve indicator.


Junghans J80/12; 680.75; balance wheel


Junghans J80/12; 680.75; Detail

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 barrel


Junghans J80/12; 680.75; main spring barrel


Junghans J80/12; 680.75; main spring barrel

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).


Junghans J80/12; 680.75; Detail


Junghans J80/12; 680.75; Detail

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...

The dial - a drama...


Junghans J80/12; 680.75; dial original

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.


Junghans J80/12; 680.75; dial


Junghans J80/12; 680.75; dial

A few have completely fallen off.


Junghans J80/12; Junghans 680.75; dial

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.

Applying the luminous mass


Junghans J80/12; 680.75; hour hand


Junghans J80/12; 680.75; hour hand


Junghans J80/12; 680.75; hour hand

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...

The result


Junghans J80/12; 680.75; Front


Junghans J80/12; 680.75; Front

Here the final result.

What has always fascinated me in the revision of the caliber is the height of the movement.

Junghans J80 12 Werk ohne Rotor.png

Junghans J80/12; Junghans 680.75; movement without rotor

After all seven millimeters!

Who needs more details to the caliber Junghans J80/12: Junghans J80/12 ; Junghans 680.75