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greg_r

User guide to the A7750 movement.

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wizawuza
4. Don’t re-set the chrono with the seconds hand anywhere but between 10 and 2 on the dial.

 

Because I'm stupid and all the double negatives confused the hell out me, I want to ask you (or whoever knows) to clarify.

Do you mean that it is okay to reset if the chrono is stopped and at 1, but it is NOT okay to do it if the seconds hand for the chrono is stopped at 3?

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DeepDiver73

just treated myself to a skyland V3 and fond this to be really useful post... thank you

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KBH
4. Don’t re-set the chrono with the seconds hand anywhere but between 10 and 2 on the dial.

 

Because I'm stupid and all the double negatives confused the hell out me, I want to ask you (or whoever knows) to clarify.

Do you mean that it is okay to reset if the chrono is stopped and at 1, but it is NOT okay to do it if the seconds hand for the chrono is stopped at 3?

 

 

What he's saying is to let the large second hand run till it's close to 12 before hitting re-set. Re-setting from far away from 12 creates too much momentum as the hand swings, which will sometimes cause the second hand to slip and will no longer re-set straight up.

 

So if you time something and it stops at 6, for instance, it's better to restart it and let the hand get back up close to 12 and then hit the re-set button.

 

 

Also, I'm pretty sure that the re-set button won't do anything unless the chrono has been stopped.

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stiltzkin
2. Yes, the 7750 rotor is usually that noisy :P

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.

 

Any idea who in the UK will service the A7750... I've read about the parts being fragile and nonreplacable.. Does this mean it's not advised to get the A7750 movement serviced?

T

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greg_r

There are no spare parts available for the A7750 - that means that very few watchsmiths are willing to work on them. Currently the best bet for EU-based members is Domi, who is based in Germany. He has a section on our sister board, RWI, but is also a member here, so PMing him is a good start.

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greg_r
How about Francesco in Spain?

 

I had been led to believe by others that Francisco is not currently servicing A7750's. Honestly I'm not 100% confident of this info, which is why I didn't mention him, although he does excellent work. Domi is extremely reliable, however.

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Leroy

pushing the 4oclock pusher (while chrono is running) puts the timing reset farther away from zero or 60 minute marker,

meaning when i stop the chrono and push reset, the chrono hand goes back to 1 minute marker (and not zero).

 

further doing this, it resets to now to the 3-minute marker, i dont want to try any more :thumbsup: maybe later... :Whistle:

 

i tried it on my daytona.

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Caliper

Silly question, I've searched but haven't found the answer yet

 

what exactly is the problem with the seconds @ 6 with the A7750 movement??

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carlton

I don't think it's designed to do that.

 

Makers will slap on an extra gear afterwards to convert it.

 

I maybe completely wrong, wouldn't be the first time !

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vfsvfl

I recently tried to step up in rep grade & bought a Pam with a 7750. So far, I am unimpressed with how it holds a charge but, thanks to this thread, I also see how lucky I must be that I haven't stripped it or otherwise ruined it already.

 

Thank you for all this useful information!

 

BTW, I infer most of the same caveats here would also apply to most 7753s?

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MikeMcNair
I don't think it's designed to do that.

 

Makers will slap on an extra gear afterwards to convert it.

 

I maybe completely wrong, wouldn't be the first time !

 

That is exactly correct. They add a few gears allowing the seconds to to be at 6 instead of 12/9 depending upon the version they use.

 

This is problematic as there are NO jewels (bearings if you will) for these gears. So, they tend to bind up or simply stop, because there is nothing but the dial and main plate sandwiching them together.

 

It's sad actually, because these movements can be VERY reliable at times (I have a few that are absolutely perfect) and sometimes they are ticking time bombs (literally)

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alw

So secs at 9 or 12 are perfectly okay?

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Luthier

12 is shit too.

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alw
12 is shit too.

 

That's what I can vaguely remember. If I ever get an A7750 it's better be secs at nine then.

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Mowgli

Worst case scenario would it be cost effective to source an A7750 as a donor and then do a swap out? Most of the Reps I am interested in use the A7750 and its also my biggest concern as I assume most UK watch repairers won't touch a Rep.

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greg_r

yup - that's often the easiest approach.

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ademarco6

So the best A7750 movement to get is the one that has sec running at 9? I am getting a POC and Tag Carerra Day/Date from Puretime and they both have sec. at 9. Also I guess the Tag Calibre RS2 with sec. wheel running at 3 is not a good one?

 

I will have to remember not to play with the chrono too much. How long before these should get serviced (A7750)? I know gens require servicing every 3-4 years, but the cost is around $500-1000 which is kind of crazy to think of dropping every 3-4 years. I have read of gen Omegas failing during the warranty and they are 3-7k watches. So I am not afraid if a crap Chinese movement fails on my rep. Just wondering how much it would cost to get a Swiss 7750 or another "new" A7750 installed and swapped on these reps. Thanks so much for the informative post.

Edited by ademarco6

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greg_r

Yep. Secs@9 is the safest one.

 

There are guys who will service these things for sensible money. A replacement A7750 movement is also an option as they're not that expensive.

 

The swap for the gen movement can be done in some circumstances - it depends on the watch (subdial spacing can be an issue). However, it's expensive as the movement itself is going to cost you $500+. Generally not worth it imho - especially as you're still going to need to get it serviced periodically.

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Member X

I just thought I would re-quote this in this thread because I think it's useful and I can never find it when I want it ;):lol:

 

This is a quote from Zig/Ziggy/The Zigmeister on RWG2/RWGjr, helpfully requoted by Sconehead today in another thread :)

 

 

 

 

Re-handwinding by Ziggy at RWG2, Feb, 2008

 

 

Handwinding an automatic has been discussed in detail.

 

Short version, it's damaging to the movement unless you wind very slowly, and only just enough to give the movement a bit of a charge.

 

All movements are prone to damage, some more than others. The 7750 is at risk and here's what happens...

 

To recap, on a 7750 if it's not running, give it a couple of turns with the crown, nice and slow, swirl the watch in your palm to get it running, put it on and leave it alone and let the autowinder do it's job.

 

IF you note any resistance or find it hard to handwind, STOP, or your going to damage the movement.

 

This type of damage is not covered by my warranty. The rotor can't cause this type of damage, it doesn't turn fast enough, or with enough force to cause this damage.

 

Note the missing teeth.

 

1.jpg

 

Another view, you can see all the teeth that have been ground down.

 

2.jpg

 

What happens to the grinding gear...it makes a mess all over...

 

3.jpg

 

4.jpg

 

5.jpg

 

6.jpg

 

New gear compared to the old damaged one.

 

7.jpg

 

I cleaned up the mess, the watch was reassembled, and is working fine.

 

Handwind with CAUTION and at your own risk.

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bill_097

so it's best to NOT hand-wind an A7750? What noise is it supposed to be making when winding? I assume winding the movement requires a clockwise motion of the crown as that provides more resistance than counter-clockwise and counter-clockwise seems to produce a clicking noise.

Edited by bill_097

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nthor71783

I have a bit of a problem. I have a Hublot King Power F1 with the 7750 movement. The second hand on the chronograph function has "slipped". The hand is not quite to the 1 second mark when in the reset-off position. Is there anyway I can adjust the hand back to it correct position?

Edited by nthor71783

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Luthier

If it's a question - you forgot the question mark.

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nthor71783

If it's a question - you forgot the question mark.

Punctuation and a spelling error corrected. I see you are a veteran of this board is my question in the right forum or should I post this in a different area or create a new thread?

Edited by nthor71783

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10:10 Watch Repair

If it's a question - you forgot the question mark.

Punctuation and a spelling error corrected. I see you are a veteran of this board is my question in the right forum or should I post this in a different area or create a new thread?

You could pose the question in Watch Repair.

The hand needs to be removed and reset. Whether or not you can do that, I have no idea, but there's no adjustment.

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