A7750 Daytona (seconds at 6)

[Greg_M]

JFC...I didn't realise the A7750 movement is such a POS! Lesson learned about doing your homework before buying....

So...any advice in terms of what does one do with a failed 7750 Daytona. Is there another movement that is more reliable - and cost effective to drop in?

Mine appears to keep stopping and I've committed what appears to be a cardinal sin of hand winding it (who knew!). I've reached out to @ado213 to discuss servicing it but for a watch that I don't love on the wrist I do kinda wonder if I've just got a paperweight now.

 

[Rx4Time]

Hand winding the movement in and of itself is not the cardinal sin of the modified 7750. The cardinal sin would be running the chronograph. The reason being is in order to change the sub dial positions they have a modifier plate installed. This modifier includes a grouping of roughly seven gears. What happens is when you run and then reset the chronograph, the gears can sometimes skip so that it doesn't completely reset to zero. The other issue that is present in some of these although most of the more recent ones have this somewhat resolved, is the running seconds hand is moved from the standard 9:00 position to 6:00. Again they use a gear train to move this and depending on if they've jeweled the gears etc they can cause a lot of resistance against the movement leading to premature failure. The only issue with winding is the 7750 in general has a higher torque gearing for the crown. I have many 7750s and I hand wind them all the time. The best thing to do is turn the crown winding at least 40 times and then see how the movement runs. I unfortunately think that the issue is in that modifier plate though and very few will touch that to be honest. You can pick up a replacement movement on eBay. I posted a link at the bottom of this response for one example. This would probably be your most economical option is to have the movement swapped out.

China Made 7753 Machanical Movement For Clone Daytona | eBay

Find many great new & used options and get the best deals for China Made 7753 Machanical Movement For Clone Daytona at the best online prices at eBay! Free shipping for many products!

www.ebay.com

 

[Geonor]

Edit: Scratch that, I should read more before I deliver my hot takes.

 

[Rx4Time]

Please note, an ETA 7750 will not work in your application because the sub dials are all in the wrong position. You need a replacement movement like the one I linked above.

 

[Greg_M]

Hand winding the movement in and of itself is not the cardinal sin of the modified 7750. The cardinal sin would be running the chronograph. The reason being is in order to change the sub dial positions they have a modifier plate installed. This modifier includes a grouping of roughly seven gears. What happens is when you run and then reset the chronograph, the gears can sometimes skip so that it doesn't completely reset to zero. The other issue that is present in some of these although most of the more recent ones have this somewhat resolved, is the running seconds hand is moved from the standard 9:00 position to 6:00. Again they use a gear train to move this and depending on if they've jeweled the gears etc they can cause a lot of resistance against the movement leading to premature failure. The only issue with winding is the 7750 in general has a higher torque gearing for the crown. I have many 7750s and I hand wind them all the time. The best thing to do is turn the crown winding at least 40 times and then see how the movement runs. I unfortunately think that the issue is in that modifier plate though and very few will touch that to be honest. You can pick up a replacement movement on eBay. I posted a link at the bottom of this response for one example. This would probably be your most economical option is to have the movement swapped out.

China Made 7753 Machanical Movement For Clone Daytona | eBay

Find many great new & used options and get the best deals for China Made 7753 Machanical Movement For Clone Daytona at the best online prices at eBay! Free shipping for many products!

www.ebay.com

40 winds...? Wow... OK Thanks!

 

[Rx4Time]

40 winds...? Wow... OK Thanks!

Yes it takes roughly 40 to 50 turns of the crown to fully charge the 7750. Other movements vary, like for example I have a couple of ETA 2894 based movements with power reserve indicator and those take about 70 turns of the crown to fully charge. After fully charged, it should run for about 40 hours give or take. If it stops shorter than that without being worn then you need to consider your options. @ado213 is a great watchsmith as are many others on here.

 

[Greg_M]

So...and I wait to be proven right or wrong on this...it appears that the 6pm second hand stops when it is sharing space with the minute hand. I can't see that there's a physical obstruction on the dial/hands so can only assume it must be something under the dial. Might this be possible?

Yes, I saw many posts recommending Adrian so have already PM'd him for advice

 

[Rx4Time]

If that's the case it's very possible that they may be making contact. That would be wonderful if it's something as simple as reseating the hands.