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Daytona A7750 with sec @ 6 issue/question


watchguy7575

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Hello,

I have a daytona with the sec @6 movement that is known for being quite horrible. I have been told about the different mods and services I can do to make it run right, and I will probably do it. It would run for about 10 minutes and then stop, and this was a common issue.

Last night, however, I felt like tinkering with it a bit. I took off the caseback, and wound the rotor by hand. It started working. I took it apart some more and then it stopped. I put it back in the case, put the rotor back on, reinserted the crown and stem, and hand wound (I know, I shouldnt), but then it started working again. I left it last night without the caseback and its running beautifully. It keeps great time (when it did work, it always did). could the case back be the reason for it to stop working?

Any suggestions would be appreciated.

Thanks

(I am posting this same thread on RG and RWG, just because I would like an answer)

 

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The caseback may be pressing on the rotor or its lower edge may be compressing some other parts. Make sure the caseback gasket is in place & not being twisted during installation of the caseback. Without seeing the watch, that is the best I can tell you (before you ask, I am not accepting any new work). Unless you can see the problem, I would have a watchmaker look at it. Keep in mind that reps are sold with used/unserviced movements & the inherent design itself is problematic. So, unless you have the movement properly overhauled & the extra gears treated with powdered graphite, there are a number of possible causes for the watch to keep stopping.

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With the caseback on, I can hear the rotor spinning when its in my hand. When I left it last night, I came back to a perfectly functioning watch. This morning, I put the caseback back on and turned it over (so it was lying on the caseback. I set it at 8:56am. I just came back and saw that it had stopped at 9:00am. So either it is the caseback (which I cant see or hear) or it the pressure put on the mainspring in any position other than crystal down? Does this make any sense?

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Is it stopping with any of the 6 hands in a particular position? That is, any chance 1 of the hands is coming into contact with the dial, index marker or another hand?

Failing that, it is either in need of a proper overhaul or an issue with the additional secs @ 6 gearing (search out my 'powdered graphite' remedy for your watchmaker).

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So now the big question is... do I have it properly serviced, swap it out for a real swiss 7750 with the secs @ 6, or just dont bother with it. The watch cost me $220 about 2 years ago, and it was fine for about 1 year (with limited wear, but nevermind). Its a standard white faced daytona rep. There is nothing particularly special, and the one thing that bugs me about it is the tachymeter bezel. It is engraved, but just barely. I have seen the gens and bezel is the dead giveaway. I havent seen a gen tachymeter bezel, and if I did, I am sure that it would be about $1000. Thats just not worth it.

 

I just need some help with this decision. Its a piece I like, but I am not in love with it. So in your opinion (professional or otherwise), what do you think I should do?

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The problem inherent with secs @ 6 7750s is the extra gearing required to relocate the running seconds. That gearing is required regardless of whether the base 7750 is Asian- or Swiss-made. Therefore, if you want to keep the correct appearance of your watch (running seconds at 6), then you will need to transplant the inherently problematic secs @ 6 gearing over to your new Swiss 7750 & you will likely end up right back where you are now (except with a lighter bank account).

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So what you are saying is that I should just use this as a watch to toy around with? Get some tools, see if I can rebuild it. Worst case, I have a pile of junk. Best case, I fixed it. In any case, I kinda lose.

 

Aside from some better screwdrivers (the home depot set I have just doesnt cut it) and some tweezers, what do I really need to take this apart and try and put it back together? Can I do this in the case without touching the dial and hands?

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So what you are saying is that I should just use this as a watch to toy around with? Get some tools, see if I can rebuild it. Worst case, I have a pile of junk. Best case, I fixed it. In any case, I kinda lose.

I've seen a fair number of WTB posts for either dead A7750s or dead sec @ 6 movements, you can probably sell it as is even if it doesn't run.

 

 

Aside from some better screwdrivers (the home depot set I have just doesnt cut it) and some tweezers, what do I really need to take this apart and try and put it back together? Can I do this in the case without touching the dial and hands?

 

At minimum you need some good screwdrivers, good tweezers, a good set of hand pullers and some hand setters. You cannot do anything without touching the hands and dial.

U need this, http://www.eta.ch/swisslab/7750/7750.html

 

start at disasemble

 

He's going to have the transfer plate stuff on top of the movement to deal with, and no calendar plate.

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Well, I may try to see what the problem is. If I cant fix it, you might be getting a bag of parts, possibly disassembled, possibly destroyed.

 

I do also have a book on beginner watchmaking and the george daniels book on watchmaking (although his is a bit advanced, describing in detail how to turn dials and make parts).

 

I have seen the eta site, and it requires me to start with the front, which means I have to take off the hands and dial.

 

It wouldnt bug me so much if the thing were dead, but as I sit here typing this, the damn thing is ticking away without any problems (as it sits without its caseback and on its crystal). As soon as I throw the caseback under it, it stops within minutes. Very frustrating

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Running dial up (or down) but not vice versa is not an uncommon failure mode for movements of all types. It's not just a sec@6 thing.

 

A sec@6 Daytona is NOT the recommended movement to start on, BTW. It's about as complicated as you can get. It's like starting with brain surgery.

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Sorry for the late reply. Although all I have at home is a nice wusthof chefs knife, I just performed my first lobotomy, and it was on myself. I think if I can do that, taking apart and putting back together a 7750 for my very first watch dissection should be a piece of cake.

 

hiorshooghuiohgjkhds,hdguirehguioshjkl;vhusriol;ghujrksl;hgur (<----- Sorry, after the surgery, my hands go kind of crazy sometimes. Good thing a balance spring is as tough as a Humvee!)

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