Development of the 156 model
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For several years Helmut Sinn had a contrat to service the Heuer 1550 SG for the German forces , even some late Heuer 1550 SG have been redialled "Sinn" : This military Heuer is equipped with the Valjoux 730 movement with flyback if you want some more infos on the Heuer 1550 SG : click here
Sinn wanted to have a sucessor to the Heuer 1550 SG : they have fitted in the same case the Lemania 5100 movement (note that case bezel and crystal are interchangeable) this was not an easy task and the access to the movement in not very easy , but for the user of the 156 this design offers a unique advantage : to be abble to change the crystals within minutes ! (see the description of the system at the end of this page)
In order to solve this problem Sinn introduce on their later versions a more traditionnal "screwback" system. (note that even if this might be concidered as a technical impovement theses later versions are less desirable to collector’s eyes)
The first model of Sinn 156 introduced on the market is without the 24 hours subdial at 12
Many different variations of the 156 exist you can have some details on theses versions in the excellent 156ER’s website : this website is in Japanese but you can use an on-line translation software like Altavista to translate it
I also recommand you the unofficial Sinn webpage (also in Japanese) where you can find informations on the 1550 SG, the 156 and 156B : click here
I have heard rumors saying that Sinn presented the 156 model to the German forces but the contract was won by Arctos, Orfina and Tutima. Sinn does supply some watches to the German forces : the 157 military issue but the 156 have never been issued.
The 156B model is now discontinued by Sinn , probably due to the shortage of Lemania 5100 movement : only few Sinn models remain powered with the Lemania
The Sinn 256 remain to the Sinn catalog : theses two watches shared a comparable design but the 256 is undersized (or is it the 156 which is oversized ?) , it really makes a big difference :
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Heuer 1550 SG
Sinn 156 first model ( from Fukubee Sinn website )
comparative picture between the 156 (left) and the 256 (right) from the excellent Fukubee Sinn website |
Here is my Sinn 156B in detail , presented like the excellent 156 owner club of Japan : 156ER’s
you can look to other 156B in detail on their website here
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General specifications of the Sinn 156B Diameter excluding the crown : 43 mm Lug width : 20 mm Thickness including crystal : 15,5 mm Movement : Lemania 5100 Weight : 70 gramms excluding the strap Water resistance : 10 ATM (100 meters)
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| Detail of my Sinn 156B |
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| Serial
number : 1313031
Shape of the "wings" on central second : Swept-back wings Inscription of luminous paint : none number of bars between the seconds : 4 Type of Sinn logo : Late version |
The "4 screws" back design
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The case opennig system of the 156B is very particular : the whole movement is hold in the case by 4 screws : This system has been already used before on the military issued Heuer 1550 SG This particular system allows the user of the watch to change the crystal easely : the only tool you need is a good srewdriver The latest models of the Sinn 156B where not equipped with this "4 screws" system , but with a more traditional "srewback" |
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| Warning : the srews are really tiny : do not loose them during disassembly : they are specific to this function and could not been replaced easely if you loose them. |
Detail of the screw
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After removing the 4 screws, gently push on the crrystal to remove the movement from the case : be very gentle : the crystal is not fixed on the inner case
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At this stage you can remove the crystal, note the two gaskets : one white in silicone and one black in nitryle : The position of theses two gaskets are very important during the re-aassembly : note carefully how they are placed |
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Close-up of the screw hole on outer case
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Close-up of the screw hole inside the outer case
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Close-up of the slot on inner case
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