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Issues: A7750 movement releasing the crown and re-locking it


munsterh

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Happy New Year to everybody!

I had a crystal exchanged in my A7750 (28800) Navitimer and have just fitted in again the movement into the case.

I have now the problem that when I lock in the crown into the movement I can only set the date but not the time in all 3 positions of the crown (in,middle and out). Have released and relocked the crown now endless times and its always the same issue: only the date moves, I can not wind the watch or set the time. Sometimes the seconds and cronograph work other times not.

Any thoughts were the problem could be?

Thanks

Munsterh

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It is really locked, yes. When I shake the watcg then it starts running, both chronograph and sweeping seconds - it stops again if I pull out or wind the crown..

Pull the crown out to the time adjustment position, remove the stem, reinsert to the same position, secure the stem...sometimes it takes a couple of tries to get it just right....Sometimes you get lucky!!..You're working with a multi- position keyless works, that was assembled by a person who most likely has no idea what he is building, in a dingy shop outside a rice paddy somewhere where rats are a delacasy!!...Proceed accordingly !!!

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Sounds like you will need to take apart the keyless works and reassemble it...It doesn't take much to misalign one of the pieces. I had a problem like the one you described. I found an ETA 7750 reference chart online and took apart the keyless works. It now works. Good luck!

P.S.

I believe Pugwash has a posting where he linked an ETA 7750 reference manual. Search under his posts...

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The stem is NOT installed properly. You will need to remove the stem and slightly loosen the stem release screw while you reinsert the stem. Be sure the stem is all the way into the movement before you snug-up the release screw. After the stem 'clicks' (locks) in, pull it all the way out to the time setting position (full out) and be sure the you can move/set the hands. Then press the crown back in (all the way) and you should hear it click back into the winding position again. If it does, then the stem is in the correct position & should work properly now.

If not, you will need to check the positions of the clutch lever (which locates the clutch wheel) and the locking plate that the stem release screw screws onto (this picture shows the keyless works -- the stem locking screw enters from the opposite side)

7750keylessworks1.jpg

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no - tried now 30 times..the wired thing is that the watch is runningnwhen the crown id removed...

What freddy said above is correct, you need to take the movement apart to fix it.

I can add that based on your comment with the movement running with the stem removed, this is due to the hacking lever having fallen out of the clutch gear, this happened when you tried to install the stem, and the only fix is to take the keyless all apart and reassemble the parts.

RG

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Guys - this is great support - I will read the links carefully but honestly I doubt that I will actuall start unscrewing the movement. I might damage in the end more than is broken at the moment...should have done a watchmakers course...

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