Francisco Posted March 2, 2009 Report Share Posted March 2, 2009 The problem we are going to repair seems to be quite common in the A7750 movement. As the video shows, when you manually wind the movement, the rotor spins: 2 Link to comment Share on other sites More sharing options...
chubbchubb Posted March 2, 2009 Report Share Posted March 2, 2009 Thanks for spending all this time to do this great writeup. Link to comment Share on other sites More sharing options...
Toadtorrent Posted March 3, 2009 Report Share Posted March 3, 2009 Thanks so much for this Francisco. I love the videos and the photos of the steps. It's beyond my skills...but certainly interesting reading to show the level of work involved!! Link to comment Share on other sites More sharing options...
Shundi Posted March 3, 2009 Report Share Posted March 3, 2009 Fransisco, thanks so much for this very in-depth and precise tutorial! i'm sure you'll save many an A7750 watch with this!! Link to comment Share on other sites More sharing options...
By-Tor Posted March 3, 2009 Report Share Posted March 3, 2009 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. Link to comment Share on other sites More sharing options...
Demsey Posted March 3, 2009 Report Share Posted March 3, 2009 i'm sure you'll save many an A7750 watch with this!! I'm sure it will too! As many a 'wannabe' watchsmith will opt to seek professional help........... Congratulations on your study and skills Francisco. Thank you for the great effort! Link to comment Share on other sites More sharing options...
Shundi Posted March 3, 2009 Report Share Posted March 3, 2009 I'm sure it will too! As many a 'wannabe' watchsmith will opt to seek professional help........... 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!! Link to comment Share on other sites More sharing options...
RWG Technical Posted March 3, 2009 Report Share Posted March 3, 2009 Well done. I use the same process just in the reverse fashion, I first clean everything in the Ultrasonic machine, then I soak the reversing wheel in one dip as I assemble the rest of the movement. Thanks again for a great post. RG Link to comment Share on other sites More sharing options...
omegaunit Posted March 3, 2009 Report Share Posted March 3, 2009 Excellent! Thank you for the info. The rotor on my Chopard chrono is starting to spin when wound. Link to comment Share on other sites More sharing options...
pv007 Posted March 3, 2009 Report Share Posted March 3, 2009 (edited) 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 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 Something I must add I cleaned the bridge too in order to make it worked ! 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 Edited March 3, 2009 by pv007 Link to comment Share on other sites More sharing options...
freddy333 Posted March 3, 2009 Report Share Posted March 3, 2009 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. 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. For those without access to One Dip, you can also use this 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. Link to comment Share on other sites More sharing options...
pv007 Posted March 3, 2009 Report Share Posted March 3, 2009 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 Link to comment Share on other sites More sharing options...
drhydro Posted March 3, 2009 Report Share Posted March 3, 2009 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! Link to comment Share on other sites More sharing options...
HauteHippie Posted March 3, 2009 Report Share Posted March 3, 2009 Francisco, thanks again for the greatly informative post. With all the 7750 information floating around lately, I'm about ready to tear one of mine down! Link to comment Share on other sites More sharing options...
freddy333 Posted March 3, 2009 Report Share Posted March 3, 2009 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. Link to comment Share on other sites More sharing options...
Velasco Posted March 3, 2009 Report Share Posted March 3, 2009 Amazing post, Francisco. As always. Thank you for sharing! Link to comment Share on other sites More sharing options...
RWG Technical Posted March 3, 2009 Report Share Posted March 3, 2009 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 Link to comment Share on other sites More sharing options...
Francisco Posted March 3, 2009 Author Report Share Posted March 3, 2009 Pv007, The Zigmeister has answered your questions very precisely. And thanks for your comments and pictures! Francisco. Link to comment Share on other sites More sharing options...
pv007 Posted March 3, 2009 Report Share Posted March 3, 2009 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... Link to comment Share on other sites More sharing options...
RWG Technical Posted March 3, 2009 Report Share Posted March 3, 2009 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 Link to comment Share on other sites More sharing options...
Toadtorrent Posted March 3, 2009 Report Share Posted March 3, 2009 If you add it all up, servicing is still the best and cheapest way to make sure your movement lasts a long time... You mean servicing PROPERLY is the best way to ensure movement longevity... A The Zigmeister Post on Bad Servicing Link to comment Share on other sites More sharing options...
dluddy Posted March 3, 2009 Report Share Posted March 3, 2009 Fantastic tutorial Francisco - thanks for sharing with the community Not anything I'll be attempting anytime soon Link to comment Share on other sites More sharing options...
801run Posted May 2, 2009 Report Share Posted May 2, 2009 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 Link to comment Share on other sites More sharing options...
Francisco Posted May 3, 2009 Author Report Share Posted May 3, 2009 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. Link to comment Share on other sites More sharing options...
801run Posted May 4, 2009 Report Share Posted May 4, 2009 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 Link to comment Share on other sites More sharing options...
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