How to open mainspring barrel of l688.2

[Anxietier]

I tried put tweezers on gears then push it, but I was afraid crash it so I didnt push heavily.

 

And that little gear, I dont know how to handle it.

[JohnR725]

found a tiny bit of information on the movement unfortunately Longines is part of Swatch group and getting technical information is going to be problematic.

then that looks like a barrel with an overhanging cover. This means that you going to have to gently pry the cover off I'm reasonably sure we've discussed this somewhere in the discussion group. typically for the Swatch group companies that replace the entire mainspring barrel. this means you have to proceed with extreme caution so hopefully somebody who has done this before will come along and help

 

https://watchbase.com/longines/caliber/l688-2

https://watchbase.com/eta/caliber/a08-l11

 

[oldhippy]

If the spring isn't broken don't open it. Clean if with rodico. A razor blade will open it but you might cause damage to the barral cap. 

[Anxietier]

thank you, I just push harder then it opened.

[jdm]

15 minutes ago, Anxietier said:

thank you, I just push harder then it opened.

Sure, but as holdhippy hinted above it's not the recommended way to open barrels, because the arbor pressing on the center can distort the lid out of flat.

[nickelsilver]

This is the same as the 7750 barrel, like John said the lid goes over the barrel rather than snap into it, so when pressing on the arbor to pop the lid off the lid actually grips harder- so as JDM said the risk of distortion is greater. Then, like OH said, you can get in between the lid and barrel lip with a thin blade and work around lifting it off. That is the safest way. I do service them (though 7750 barrels are cheap and often just replace the whole thing), and have never had an issue using a blade to open and a normal barrel closer to reassemble.