Rolexman Posted February 12, 2011 Report Share Posted February 12, 2011 I received a Navy with the 7750 (28.800) movement. Chrono second hand ran smooth. Gave it a service, chrono second hand runs jerky So I changed the clutch, chronograph wheel and oscillating pinion to ETA, just to be sure...... still jerky Running seconds are smooth BTW so the train gear is okay. So now I think it perhaps has something to do with friction wheel. What to you guys think? Thanks! Quote Link to comment Share on other sites More sharing options...
Bike Mike Posted February 13, 2011 Report Share Posted February 13, 2011 Check to make sure both the jewels are not varnished up... Try hitting them with a little One Dip and sharpened Pith Wood. Quote Link to comment Share on other sites More sharing options...
Rolexman Posted February 13, 2011 Author Report Share Posted February 13, 2011 Check to make sure both the jewels are not varnished up... Try hitting them with a little One Dip and sharpened Pith Wood. Thanks Mike. All jewels, plates and posts are clean as a whistle. I'm running out of options. Think I will try cleaning the nylon bushing of the friction wheel an bending the spring a bit... see what that does Quote Link to comment Share on other sites More sharing options...
Bike Mike Posted February 14, 2011 Report Share Posted February 14, 2011 Let us know what you find out...Only other thing I can think of is the nylon bushing is okay, is the tilting pinions engagement...but it sounds like you may have tried that already. Quote Link to comment Share on other sites More sharing options...
Rolexman Posted February 15, 2011 Author Report Share Posted February 15, 2011 Well, it wás the friction spring! It was not providing enough upwards tension (rotor side). Therefor the oscillating pinion teeth weren't engaging properly and the movement was jerky. You were right on the money Mike. Hopefully this post will provide some helpfull information in future searches @ Bike Mike thanks for your contribution. Nice to know I can always count on your usefull insights! Quote Link to comment Share on other sites More sharing options...
Bike Mike Posted February 16, 2011 Report Share Posted February 16, 2011 Anytime! Glad you narrowed it down and got her fixed. I have learned to look for "spring back" on the 60sec. Chono Wheel after running across a couple movements where the jewel setting on the Automatic Winding Bridge was tweeked. It was out of place just enough to allow for no up/down movement on the chrono wheel, causing either complete lock up with the chrono's active or the sweep second hand not to run smooth. One more thing for you to look for! Quote Link to comment Share on other sites More sharing options...
Recommended Posts
Join the conversation
You can post now and register later. If you have an account, sign in now to post with your account.