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Repairing when you manually wind and the rotor spins (7750)


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Once again: Thanks Francisco. Another excellent tutorial.

Me and my clumsy, big hands would only do serious damage to these movements. That's why I leave all of this stuff to the professionals.

PS: We could give you your own section but we're afraid that these articles would be "lost" in the huge subforum -> subforum of a subforum jungle/maze that RWG has become. Perhaps these articles would get more coverage and attention if you composed a post that has all these reviews linked. Then that could be stickied in Watch Repair and Upgrade section. You could update the post always when you post new stuff. You could also link them into your signature. Let me know.

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I'm sure it will too! As many a 'wannabe' watchsmith will opt to seek professional help........... :D

Congratulations on your study and skills Francisco. Thank you for the great effort!

Well played- Many somewhat problematic 7750s may become VERY problematic 7750s (IE- those of us with big fingers messing about with small gears). Starving watchmakers will love us!!

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Finally Francisco the tutorial

Thank you very much !

I can add some stuff, I had many problem using this method indeed the reversing was still gummed up and I put it OneDip and MAGIC everything works after that

Francisco gave me the idea of that and it was a nice idea as OneDip add a sort thin "moisture" protection...

Francisco i posted a question somewhere but I found no answer for it:

The ETA reversing wheel has to be cut down as pivot is too big but I noticed that the ETA Bridge is not really different from the Asian wheel but the whole (jeweled) that hold the reversing wheel pivot which is much

bigger... Do you think by adding a new ETA bridge the ETA reversing could fit ? that could be a nice thing to try

Because I already asked all my connection for reversing wheel parts and it is not possible to get an Asian one, you need to order the whole movement

the one who is going to sell one day reversing wheel will certainly earn a lot of money, I would buy 20 of theses !

This topic has to be pinned :)

Something I could add in order to help for the noob like me correct me if I'm wrong

You can get rid of tilting pinion assembling using this method but you have to be really precise

post-5222-1236049294_thumb.jpg

Remove the rotor

Remove the clutch spring

Remove the Hammer spring

Then put rodico just near the bridge in order to hold down the clutch (use high end rodico as you don't want to leave some rest when you will remove it)

then you can remove very carrefully the bridge and you will have have your clutch hold by rodico

post-5222-1236049312_thumb.jpg

Something I must add I cleaned the bridge too in order to make it worked !

post-5222-1236049307_thumb.jpg

After all that if it's not working then send back your watch as I have with one of mine

no reversing wheel left...

Cleaning/lubrificate worked for on 2 of 3 non working watches

post-5222-1236049301_thumb.jpg

Edited by pv007
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I used a two steps cleaning. First one, using One Dip. If you do not have it, move to ultrasonic cleaning. One Dip is a very powerful grease remover (and very toxic) employed in watchmaking.

img1695.jpg

The reversing wheel is immersed in the One Dip bottle. Shake it very gently and leave it for at least 10 minutes.

Great write-up, Francisco. :good:

For those without access to One Dip, you can also use this

brakecleaner1.jpg

Brake cleaner (tetrachloroethylene) is chemically similar to One-Dip (trichloroethylene) & their cleaning/degreasing properties (at least as they relate to shellacked watch parts like balances & pallets) are functionally the same. Spray the brake cleaner into a small jar (do this in a very well-ventilated area), place the part into the jar & then agitate the jar for a minute or 2.

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I have to add to my tips up

Then after all that cleaning, re-assemble all the stuff back

and watch out for the rodico don't leave some of it under the bridge when you put it back.

Remove the rodico, you will certainly leave some first then you will get the tricks

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Just a couple of comments-

One-dip is great stuff. I've found that I get better results if, after the one-dip soak (and I've lately been using a small beaker of one-dip in the ultrasonic), I carefully blow the gear dry with an aerosol duster can. That leaves it *perfectly* dry, ready for the 9010 oil... and they really mean just a little bit!

The other comment has to do with brake cleaner. Freddy's right that tetrachloroethylene's chemically similar to trichloroethylene, but two caveats: it is less volatile, therefore dries much more slowly- AND "brake cleaner" isn't always tetrachlor, varies a GREAT deal in composition and purity- you can try various brands of the stuff, but spray it onto a clean glass pane and see how it evaporates and whether it leaves a residue before you use it on your watchies!

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Good point, drhydro. You definitely do not want to use the non-chlorinated form (check the label for ingredients containing the word chloroethylene). One Dip, for the reasons drhydro stated, is preferable to brake cleaner. But brake cleaner will definitely do the job if One Dip is not available.

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The ETA reversing wheel has to be cut down as pivot is too big but I noticed that the ETA Bridge is not really different from the Asian wheel but the whole (jeweled) that hold the reversing wheel pivot which is much bigger...

I have modified the ETA reversing wheel, and the ratchet driving wheel (1482) by cutting the pivots down on the lathe and making them fit the Asian 7750...the problem is the time it takes to do the lathe work, and the cost of the ETA parts...it isn't economical to use this as a fix for the problem.

RG

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I have modified the ETA reversing wheel, and the ratchet driving wheel (1482) by cutting the pivots down on the lathe and making them fit the Asian 7750...the problem is the time it takes to do the lathe work, and the cost of the ETA parts...it isn't economical to use this as a fix for the problem.

RG

You are right master The Zigmeister, not all people has the chance (and the skill) to have and use a lathe and this operation could be really different difficult when you see the size of the Reversing Wheel

and the price for the ETA part is really expensive ...

I don't understand why factory does not sell spare parts of their A7750 especially the parts we cannot find ...

Someone, someday should try to get this wheel as it becoming really common' these days

I received 5 watches with this problem and had a very hard discussion with my seller because he said that I was lying to him until I sent one day a video with an explaination on how I fixed the problem ...

I repaired 2 of them and sent back the rest because of the lack of spare parts...

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Spare parts is a big problem, all the more reason to have the movement serviced so you don't damage the gears in the autowinder.

The other solution would be to replace the jewels for these gears with the ETA jewels and gears...I haven't tried it, but it should be possible...just expensive that's all...

If you add it all up, servicing is still the best and cheapest way to make sure your movement lasts a long time...

RG

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  • 1 month later...

Great writeup Francisco! Your writeups are always great!

Too bad I didn't have your post in front me when I tried this out a month ago or so =)

I had this spinning-rotor-while-winding problem with an a7750 in a Montblanc Timewalker, there were lots of other problems with this movement as well, the chrono reset button was stuck due to the switch (55.271) being out of place on the dial-side, the yoke was out of place due to some bad luck reinserting the crown. Reinserting the crown actually was the thing that caused all movement errors for me in the first place .. incl spinning rotor problem. Before I tried this repair out I had no idea what so ever about the nature of these problems. I read a few posts, got som very valuable info from Watchdog, Toad and others here at the forum, found some tutos here and there, especially this thread from Toads guide is intereseting -> http://www.rwg.cc/members/Pictorial-Unders...+rotor+spinning .. gives you understanding about the nature of the spinning rotor problem, why hand-winding is bad, as well as some info on what gen parts are directly interchangeable with a7750 parts and which are not.

I decided to try the repair, so I bought a few tools (screwdriver, movement holder and tweezer) and a few chemicals (acetone for cleaning and moebius D5 oil for oling parts afterwards (this isn't the correct oil for all parts, but the budget I set for this project allowed for one oil only, so I chose the D5)), also bought some spare gen ETA parts, thought it could be handy to have .. bought couple ratchet wheels (this is the wheel that might loose its teeth when handwinding, thought I might be prepared with couple of new ones here if necessary, since this part is cheap and directly interchangeable according to the thread above) and one reversing wheel, also some date wheels .. thought why not change date wheel while at it, bought all stuff from cousins uk.

Why do you guys say it is not economical buying the gen ETA reversing wheel, its only

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I have just installed the ETA reversing wheel, without any mod..and works perfectly... I have to check it up... but at the moment works very well...

Francisco.

That is great news Francisco!

I wonder if the complete A7750 balance would be interchangeable with the gen ETA complete balance. The ETA complete balance is

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