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IW 3717 chrono broken?


XFi

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Hi guys, I have a question.

I have a 3717 with A7750 and I just lost all the pressure on my pushers (both) and the chrono stopped working. What is wrong? Is this serious? How, and more importantly who would be able to fix this at what price? Would sending it to someone for a full movement 'cleaning' be the best option? Who would you recommend? I'm from Belgium...

Thanks a lot guys!

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Here is the chrono functions with rotor removed. TopPlateFullChronoDscn0756.jpg Some movements chronos will break after playing for some time and when chrono is running, you can press reset pusher and it bends the lever inside, on some you can press reset pusher and nothing happens, that's because they have lever inside witch moves away from the reset pusher tip. If you press stop pusher then lever moves back to in front of reset pusher tip and then you can reset the chrono. Metal is soft and it bends, some have better quality and will work long time. On my example, the reset function didn't work after 10th time or so and when I did open the case back I saw the lever (nr 4 on pic) was slipped out of place with hammers (nr 5 on pic). You can read here how chrono in 7750 works: http://www.timezone.com/img/articles/horologium631672313433425752

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  • 2 weeks later...

Thanks a lot! I'm really not familiar with movements. Do you think it's safe to bring it to a regular watch smith and tell him to have a look if I pay them? Just don't want to screw up to whole movement... Plus I have no tool to open the caseback :)

 

Can a regular watchsmith also perform a movement cleaning?

 

Cheers! 

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MAke sure they are competent! My father brought his Laureus Ingy to a regular watch smith and they could not even put the seal back in place after realizing that they had no clue what that movement was....

 

A kid's play ball is what I use to open the case back.  I bet it is only the screw from the operating arm of the chrono that is loose or fallen.  I had a similar issue with my u-boat flightdeck when I first got it.

 

I just received my U-Boat Flightdeck 50mm 2 days ago. At first I did not want to use the chronograph because of all the horror stories I have read on the forums. But I thought I would give it a try.... Very, very, very hard to press.... In fact, I cannot press hard enough to start the chrono. After a few trials I come to the conclusion that my 7750 does not work properly. Cry.gif

Looking on the forum, I have found some very useful info:
http://www.eta.ch/swisslab/7750/7750.html

I have noticed that the Operating Arm (Pink) was not going under the cam (light blue) as it should. I was kind of sitting to high.
7750Chrono.jpg

After many trial with the watch in different angle, I could not get it to work. So I wrote to my dealer and he proposed to fully wind the watch (40 turns ) and to try to press harder. Knowing that the 7750 does not like to be manually winded, I went very smoothly. But still the same. The operating arm hits the cam to high and blocks.

Since I am hard headed, I was convinced that my theory was right! I started to shop for a tool to open my 50 mm screw cover and I discovered the "Rubber Ball Trick". My Son had just what I needed ;)

Took 30 seconds to open the case and 10 second to notice that the screw retaining the operating arm was loose, causing it to be sitting to high and contacting the wrong part of the cam. 5 Minutes later I have a functional chrono very smooth to start and stop!! biggrin.png

Now can I call myself a Watch smith? Whistle.gif

RPT_MG_3784.jpg
RPT_MG_3745.jpg
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Thanks for your reply, Mirage. Might look for a ball like that to open my watch.

 

However, I'm a bit afraid I won't know what's wrong and then I'm not helped anyway :)

 

My issue is that both pushers don't have ANY resistance (they were quite tough to push in the beginning, and at some point they lost all pressure and the chrono doesn't work anymore :)

 

Let's see...

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