# Do All 7750 Movements Stutter?



## sheepsteeth (Dec 14, 2009)

The plan is to buy a 7750 chrono based watch in the near future.

i had a little look on youtube to find out what they go like (i wondered if the chrono ticked or swept) and was supprised to see that the watch i want to buy, has a 7750 movement which seems to stutter, could this be a one off or do 7750 movements tend to have a stuttering second hand when the chrono is running?

to clarify, the small second hand looks to sweep beautifully and uniformly, it was just the chrono second hand which seemed to stutter. It's not a deal breaker for me, i remember having a benarus with a miyota movement which stuttered but didnt seem to lose any accuracy.


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## mrteatime (Oct 25, 2006)

should be smooth? all the 7750 movts have the "wobble" but never seen one that effects the actual sweep on any sub dial....the only 7750 movt watch i have here doesnt have a stutter as such but it doesnt sweep as smoothly as the minte hand....


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## DaveS (Dec 7, 2009)

The 7750 runs at 28800 bph so the small second hand runs at 8 bps. I have two watches with 7550 movements, one a COSC (Ventura) and one a bog standard 7750 movement, On both watches the chronograph seconds hand seems to run at about 6bps and you can see the hand moveing in 1/6 second "jumps" rather than smoothly. I would think this is normal. Is this what you mean by "stutter"?

Kind regards

Dave


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## tixntox (Jul 17, 2009)

6 beats a second is pretty smooth on my 7750. Is it ETA, Valjoux ......... or Chinese perhaps?

Mike


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## sheepsteeth (Dec 14, 2009)

tixntox: it is a valjoux 7750 according to the manufacturer.

DaveS: it might be the lower bpm and in hindsight it could be to do with the quality of the video i was watching. Do both versions of your 7750 behave similarly when in chrono mode?

thanks for all of the replies so far.


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## tixntox (Jul 17, 2009)

Just had a look at mine (my 7750 that is! :blush2: ) and it appears very smooth, even under a loupe! Some watches have thick second markers which may give the "jumpy" appearance? 

Mike


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## DaveS (Dec 7, 2009)

tixntox said:


> 6 beats a second is pretty smooth on my 7750. Is it ETA, Valjoux ......... or Chinese perhaps?
> 
> Mike


Hi Mike

I guess it depends what we interpret by "smooth" and what "sheepsteeth" describes as "stutter".

Both my watches have Valjoux (ETA) 7750 movements. One (Ventura) has a COSC graded movement, the other (Hamilton) has a basic movement. Both are equal in terms of their timekeeping (ie well within COSC specs). For both I can see the chronograph second hand moves in discrete movements which I estimate to be at a rate of 6 pbs. Most "normal" people would describe this as smooth but we WIS aren't normal are we? I'm just trying to get some feeling for what sheepsteeth means by "stutter". I may need to get one of my off-spring to post a video.

Kind regards

Dave


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## tixntox (Jul 17, 2009)

DaveS said:


> tixntox said:
> 
> 
> > 6 beats a second is pretty smooth on my 7750. Is it ETA, Valjoux ......... or Chinese perhaps?
> ...


I'm not even going there after the last couple of days! 

Mike


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## sheepsteeth (Dec 14, 2009)

thanks again for the replies, if its easier to show the video im am refering to, i can post a link?


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## DaveS (Dec 7, 2009)

sheepsteeth said:


> thanks again for the replies, if its easier to show the video im am refering to, i can post a link?


Hi

That would be helpful.

Thanks.

Kind regards

Dave


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## sheepsteeth (Dec 14, 2009)




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## Dick Browne (Dec 16, 2008)

That could be due to the mesh between the oscillating pinion and the chrono runner - it's adjustable with a screw. Also, the upper bearing surface for that pinion isn't jewelled, it's just a hold drilled in a metal pressing, and these can wear oval over time.

Either one of those can cause stutter similar to that in the video, luckily they are both cheap fixes. A proper Valjoux 7750 should sweep smoothly if it's properly serviced and adjusted. The Asian clones are slightly more variable, but should still be smooth.


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## DaveS (Dec 7, 2009)

Thanks for the video sheepsteeth.

No, the 7750 movement does not stutter like that. I guess this is to do with the frames per second of the video which I guess is about half the rate of the chrono hand, This makes the chrono hand look as though it's moving in pronounced jumps. The actual movement is much smoother tham this.

Hope this helps.

Kind regards

Dave


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## sheepsteeth (Dec 14, 2009)

Thanks again for the replies folks.

the plan is to buy this model (steinhart Nav-b chrono 47mm) as, to my mind atleast, it is a fantastic looking watch with a swiss movement for a good price.

Could i be overlooking a different but similarly specced watch like this from another manufacturer?


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## Defender (Jan 27, 2009)

Hi I only have one to hand at the moment, the other will be 'in coming' later this month!

However the one in my Fortis B42 Pilot Professional seems to tick quite nicely, as mrteatime says there is a bit of a stepping motion, it's not quite as smooth as some other mechanical watches I have, or the seconds sub dial come to that, but nothing like the one in the clip.

ATB,

Defender :astro:.


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## DaveS (Dec 7, 2009)

sheepsteeth said:


> Thanks again for the replies folks.
> 
> the plan is to buy this model (steinhart Nav-b chrono 47mm) as, to my mind atleast, it is a fantastic looking watch with a swiss movement for a good price.
> 
> Could i be overlooking a different but similarly specced watch like this from another manufacturer?


PM sent.

Kind regards

Dave


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## pugster (Nov 22, 2004)

i have a few 7750's , none of them 'stutter' , the wobble ppl talk about comes from the rotor afaik.


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