- 30/3/08
- 43,333
- 16,206
- 113
The below is a re-post from RWG1.1 so thanks to greg_r
The 7750 is probably the most-discussed movement on the rep boards. Partly because of the notorious issues with the secs@6 movements (now a little improved with the latest version), but also because it has built a reputation for being less reliable than other movements. The reliability issue is, however, largely based on early samples of the low-beat version - the movement currently being fitted to replica watches is much more consistent and, if treated correctly, is as reliable as one could wish for something that is, essentially, very inexpensive.
Here are a few basic guidelines - culled from posts by Ziggy and various other folks who know a damn sight more about this movement than I do
.
1. If you have to hand-wind the movement, do so gently and try not to do it too often. The hand wind mechanism is quite high-geared and there is a danger that you can strip the gears if you're too rough with it. Best advice is to start the watch with a quick 'swirl' then just strap it on and wear it. Normal use should keep it wound (I can vouch for this as it's what I do.).
2. Yes, the 7750 rotor is usually that noisy
The 7750 rotor only winds in one direction. The winding direction has resistance since the rotor is trying to wind the mainspring. In the other direction there is no resistance at all, and the rotor is free to spin. If the rotor bearings are dry, there is nothing preventing the rotor from spinning like crazy. Lubricating the bearings helps to quieten the rotor a bit and prevent such a free spin in the non-winding direction.
3. Don’t set the date between 7 pm and 2 am
This is true for all 7750’s, Asian or gen Valjoux. Note that this is also good practice when setting the date on other movements. The date gear starts to engage with the date wheel around 7pm and disengages totally by 2 am, if you attempt to do a quick date change during the engagement, you will damage the watch. Best advice - with any watch, whatever the movement - is to wind the hands forward past midnight until the date changes, then with the hands set to around 6am, use the quick set function to change the date as needed.
4. Don’t re-set the chrono with the seconds hand anywhere but between 10 and 2 on the dial.
The reset hammer can slam down very hard onto the heart cams for the seconds and minute counters. This force can cause the seconds hand to slip if the hand is sitting anywhere but between 10 and 2. Even genuine watches can suffer from this problem. A slipping center seconds hand is totally preventable by the owner, all you have to do is make sure you never reset your chrono between anything but 10-2. In addition, DO NOT push the chrono reset pusher (@ 4) while the chrono hand is running. It is also recommended that you resist the temptation to 'play' with the chronos too often - especially on an unserviced movement - as this can increase the chances of problems.
As I said - this post has been collected from comments by various experts on the boards. If more knowledgeable folks than myself have any corrections or observations, do please feel free to comment and I'll correct this post if appropriate. Thanks.
The 7750 is probably the most-discussed movement on the rep boards. Partly because of the notorious issues with the secs@6 movements (now a little improved with the latest version), but also because it has built a reputation for being less reliable than other movements. The reliability issue is, however, largely based on early samples of the low-beat version - the movement currently being fitted to replica watches is much more consistent and, if treated correctly, is as reliable as one could wish for something that is, essentially, very inexpensive.
Here are a few basic guidelines - culled from posts by Ziggy and various other folks who know a damn sight more about this movement than I do
1. If you have to hand-wind the movement, do so gently and try not to do it too often. The hand wind mechanism is quite high-geared and there is a danger that you can strip the gears if you're too rough with it. Best advice is to start the watch with a quick 'swirl' then just strap it on and wear it. Normal use should keep it wound (I can vouch for this as it's what I do.).
2. Yes, the 7750 rotor is usually that noisy
The 7750 rotor only winds in one direction. The winding direction has resistance since the rotor is trying to wind the mainspring. In the other direction there is no resistance at all, and the rotor is free to spin. If the rotor bearings are dry, there is nothing preventing the rotor from spinning like crazy. Lubricating the bearings helps to quieten the rotor a bit and prevent such a free spin in the non-winding direction.
3. Don’t set the date between 7 pm and 2 am
This is true for all 7750’s, Asian or gen Valjoux. Note that this is also good practice when setting the date on other movements. The date gear starts to engage with the date wheel around 7pm and disengages totally by 2 am, if you attempt to do a quick date change during the engagement, you will damage the watch. Best advice - with any watch, whatever the movement - is to wind the hands forward past midnight until the date changes, then with the hands set to around 6am, use the quick set function to change the date as needed.
4. Don’t re-set the chrono with the seconds hand anywhere but between 10 and 2 on the dial.
The reset hammer can slam down very hard onto the heart cams for the seconds and minute counters. This force can cause the seconds hand to slip if the hand is sitting anywhere but between 10 and 2. Even genuine watches can suffer from this problem. A slipping center seconds hand is totally preventable by the owner, all you have to do is make sure you never reset your chrono between anything but 10-2. In addition, DO NOT push the chrono reset pusher (@ 4) while the chrono hand is running. It is also recommended that you resist the temptation to 'play' with the chronos too often - especially on an unserviced movement - as this can increase the chances of problems.
As I said - this post has been collected from comments by various experts on the boards. If more knowledgeable folks than myself have any corrections or observations, do please feel free to comment and I'll correct this post if appropriate. Thanks.
