Interesting mid 70s Longines electronic
Restored this Longines electronic last year. I seem to be attracted to watches with impossible to source crystals 😅.
Posted a before and after picture. Uses an ESA 9158 movement. The second electronic balance movement that ESA made.
It is probably one one the first uses of this movement. Since to my knowledge they only became available in 1975 and the serial number puts production of this watch to 1974.
It is quite a bit different then it's predecessor the 9150.
The 9158 gear train is quite simple and has no anchor/pallet fork. Instead it has a tiny magnet in the main plate that lines up the escape wheel. Honestly it's very stupid and I can't believe it works.
Also very bad case construction water resistance seemed to be an after thought but they still tried to put gaskets in 🤨.
The watch had a broken balance staff. Thankfully parts are readily available for it so it was a pretty quick fix.
"I too worship the God of Delusion" -that guy in the back alley.
There are lots of parts for this movement online as it is not a very rare movement.
In this case I changed the whole balance complete, as the balance wheel is made out of aluminum and is very easy to damage. There is no point to change just the staff, if parts are readily available. I would only do that on a watch like this if there was no other option.
Fabulous! Great that people keep these intermediates working! I want to buy an electronic movement watch.. but I might buy two with the same movement just in case...😂
Fabulous! Great that people keep these intermediates working! I want to buy an electronic movement watch.. but I might buy two with the same movement just in case...😂
Honestly if you are going to go for one I would recommend a Citizen Cosmotron X8. They are very well built. Citizen put a lot of research into electronic balance technology.
The ESA 9150 is also solid and has lots of parts available for it. Many brands used it.