# I've Faced My Demons...



## Silver Hawk (Dec 2, 2003)

I have a few "rules" before working on other people's watches:

1) I must have (or be able to get) spare parts in case I break anything

2) I must have worked on my own examples of the movement...and be totally confident with the movement

:yes:

Now anyone who has worked on the Omega Speedsonic movement will have nightmares thinking about the chronograph module :fear:. It was ESA who secretly started work in 1970 on the development of a tuning fork chronograph. They took their existing ESA 9162/4 movement, as used in tens of thousands of Omega f300s, Tissot Tissonics, Longines Ultronics etc, and managed to add a chronograph layer to the movement....it was finally released in 1972 and is known as the ESA 9210 although many watch makers allocated their own calibre number to it --- the Omega version is known as cal. 1255.

I have a huge amount of respect for these ESA movement designers of the early 1970s. How they managed to design this chronograph module without the aid of computers is beyond me...maybe they did use early computers...anyone know? The ESA 9210 was the only tuning fork chronograph even manufactured.

A couple of years ago, I had cause to "open up" the chronograph module on one of my Speedsonics. It came apart really easily :lol:. But it took me 3-4 days to get it back together again and I vowed never to work on this module again. So when people asked me to service their Speedsonics, I would always say "Yes, fine, as long as the chronograph module is working correctly, as this part is not included." and, to be fair, the chronograph module usually doesn't play up unless battery corrosion has got to it...

When I won the Baume and Mercier Tronosonic Chrono a few months back, I put it's rather sad, broken ESA 9210 movement to one side and replaced it with a NOS movement. But this weekend, I decided to face my demons and restore the old B&M movement which inlcuded a full strip down of all module....even the chronograph one.

I had one advantage this time...compared to my disastrous efforts 2-3 years ago....I now have a service manual for the Longines L749.2 movements (Longines branded ESA 9210). And I have to say, with the manual, things went a whole lot easier and that 3-4 days reassembly shrunk to less than an hour!

I've now stripped it down and re-assembled it a couple of times over the last weekend and on the final (?) time took photos of each layer. Sorry for rambling on, but hope you like them:

1) Photo of the assembled movement from the oscillator side. At this stage, looks like any normal ESA 9162 / Omega f300 movement:










2) Side view of the movement showing the 4 plates / platforms. A normal ESA 9162 / Omega f300 movement has only 2 plates










3) Now on to the strip down. First the Upper Plate (101). This is nearly identical to a normal ESA 9162 / Omega f300 movement and makes up the oscillator uint (tuning fork, coils, electronics, index wheel, indexing pawls etc):










4) Next we have the Main Plate (100). This houses the keyless works and shares only a few parts with the normal ESA 9162 /Omega f300 movement. You'll notice that the nickel plating has largely been lost on this plate due to battery corrosion. I re-newed the Train Wheel Bridge which is why that looks so much better. The loss of nickel

doesn't affect the movement










5) The Chronograph Mechanism Platform (8281). Undue those 4 screw around the periphery at your peril :stop:! This is back (oscillator side) of the chronograph module and shows the wheels driving the 3 sub-dials.










6) The Calendar Platform (2551) viewed from the oscillator side. This is what used to frighten me...but not anymore :lol:! The two chrono buttons correspond to the two round posts at 10 and 8 in the photo below. The mechanism is currently in the running position i.e. the wheels are all free to turn. What is not clear in this photo is that the two wheels with brass foils on their tops are first located into the large sliding steel plate (Reversing Yoke Lever 8180) before the plate + wheels are offered up to the main plate --- their zeroing hearts are underneath this yoke lever. The whole chrono mechanism is under tension here due to the numerous springs...and there are another three hammer springs that you cannot see in this photo....so you have to be very careful when replacing the plate that covers this :yes:.










[more]


----------



## Silver Hawk (Dec 2, 2003)

7) The Calendar Platform (2551) viewed from the oscillator side. Another shot of this plate but now with most of the chronograph mechanism removed. All that is left are the three hammers and their springs for zeroing the two sub dial hands and the main centre second hand.










I've only shown you one side of each of the four plates / platforms...there is just as much going on on the other side  . If anyone wants to see those photos as well, just ask and I'll post them.

Having now studied this movement, it seems to me that this is one chronograph that is best left with the chrono function running. The reason I think this is because these sub-wheels are never dis-engaged from the main movement --- when the chrono function is in the "stop" or "reset" position, the hammers-on-the-hearts etc are stopping the sub-dials turning and it is slipping clutches on all three wheels that allow the rest of the movement to carry on running. Clutches will wear out.


----------



## jasonm (Nov 22, 2003)

Great stuff Paul... This has the making of another classic topic.....

I'm constantly amazed at how such small parts were made consistently .....


----------



## dobra (Aug 20, 2009)

Superb explanation and piccies Paul. I will have to re-read again, as I have never had sight of such an intricate piece of engineering.

More please!

Mike


----------



## Rotundus (May 7, 2012)

:yahoo: :thumbup: :notworthy: :lol: :yes:


----------



## Who. Me? (Jan 12, 2007)

Well done. How many times did you have to play 'hunt the spring'?

I've wondered about running the Chronograph all the time. When my Speedsonic Lobster arrived back from Bienne it was running and I'd wondered whether that was due to mis-handling in the post. Anyone else had one serviced by Omega or STS, and did it arrive running or stopped.

I try to run mine for a day every few months to stop everything gumming up (figure if the oils dry out it'll stick or there will be extra resistance at particular points, like flat spots on tyres, if they've been left standing).

I've got another question that your strip down might answer - what damage would be caused if the reset is pressed while the Chronograph is running? I've never tried (didn't want to risk a repair bill). Your last photo on your first post above shows a lever towards the middle of the plate at 8 o'clock. It looks like it's affected by the start/stop sliding plate? Does that interfere with the 'reset' sliding plate to prevent it being engaged while the start/stop sliding plate is in the 'running' position?

I'd like to see pics of the rest, if you've got time. The German service manual that I downloaded ages ago is a really poor copy. Your photos make it a lot clearer how the parts interact.


----------



## Who. Me? (Jan 12, 2007)

Sorry, another nerdy question, what does the part on the periphery of that calendar platform, at 4 o'clock (resting against the reset sliding plate) do? At the moment it also looks like it would stop the reset plate sliding back?


----------



## tixntox (Jul 17, 2009)

Amazing stuff Paul. :yes: Great job. :sweatdrop: You have my admiration for even thinking of going there. :thumbup:

Mike


----------



## Silver Hawk (Dec 2, 2003)

Who. Me? said:


> I've got another question that your strip down might answer - what damage would be caused if the reset is pressed while the Chronograph is running?


You shouldn't be able to press the reset button when the chrono is running. In the image below, the fly-back-yoke bolt prevents that.












Who. Me? said:


> Sorry, another nerdy question, what does the part on the periphery of that calendar platform, at 4 o'clock (resting against the reset sliding plate) do? At the moment it also looks like it would stop the reset plate sliding back?


Not sure which one you mean. There is a locating peg for the top plate --- same as the one at 8, 11 and 2


----------



## PC-Magician (Apr 29, 2013)

Well if Paul couldn't do it no one else could that's for sure.

I am sure you must be related to Einstein.

By the way the MQ you serviced for me is keeping superb time.

Jon


----------



## Silver Hawk (Dec 2, 2003)

dobra said:


> Superb explanation and piccies Paul. I will have to re-read again, as I have never had sight of such an intricate piece of engineering.
> 
> More please!
> 
> Mike


Thanks Mike. The next set of photos shows the other side of the plates / platforms starting from the dial side:

1) Calendar Platform (2551). Built up with all calendar parts plus some hands that I used to test the movement.










2) Calendar Platform (2551). Partially dismantled.










3) Calendar Platform (2551). Fully dismantled.










4) Chronograph Mechanism Platform (8281). Dial side.










5) Main Plate (100).










6) Upper Plate (101)


----------



## pugster (Nov 22, 2004)

great and informative write up paul .. and great work as usual , i have a love/hate relationship with tuning fork watches but they still fasinate me.


----------



## Who. Me? (Jan 12, 2007)

Silver Hawk said:


> Who. Me? said:
> 
> 
> > I've got another question that your strip down might answer - what damage would be caused if the reset is pressed while the Chronograph is running?
> ...


Great. I know it's daft but that's been bugging me as a 'risk' with these movements.


----------



## Who. Me? (Jan 12, 2007)

Who. Me? said:


> Sorry, another nerdy question, what does the part on the periphery of that calendar platform, at 4 o'clock (resting against the reset sliding plate) do? At the moment it also looks like it would stop the reset plate sliding back?





> Not sure which one you mean. There is a locating peg for the top plate --- same as the one at 8, 11 and 2


The bit that the red arrow is pointing to...










In the current position, the projection on that part, which the blue arrow is pointing at, looks like it's also stopping the reset sliding plate ('reversing yoke lever'?) from sliding back?

But the important bit you've answered above - shouldn't be able to press reset while it's running.

Cheers Paul

Andy


----------



## Littlelegs (Dec 4, 2011)

Very informative and makes me wish I had the ability to strip and rebuild this sort of thing. I can just about manage working on car/bike engines but the intricacies of these watches scare the life out of me. Top work...)


----------



## Silver Hawk (Dec 2, 2003)

Who. Me? said:


> Who. Me? said:
> 
> 
> > Sorry, another nerdy question, what does the part on the periphery of that calendar platform, at 4 o'clock (resting against the reset sliding plate) do? At the moment it also looks like it would stop the reset plate sliding back?
> ...


The red arrow points to the fly-back-yoke jumper...and looking at the angles, I don't think this would stop a push of the start/stop button. In fact, I think this is the part that gives the firm "click" when you push the top button. You're actually pushing the fly-back-yoke past this jumper and its spring. Nothing else acts on this jumper, so I'm sure it is responsible for the "click".


----------



## Muddy D (Nov 16, 2013)

Hi Paul,

Great post. I've not serviced a watch before though am now feeling inspired to get a manual and some practice watches, do you have any tips for a novice?


----------



## Who. Me? (Jan 12, 2007)

Silver Hawk said:


> The red arrow points to the fly-back-yoke jumper...and looking at the angles, I don't think this would stop a push of the start/stop button. In fact, I think this is the part that gives the firm "click" when you push the top button. You're actually pushing the fly-back-yoke past this jumper and its spring. Nothing else acts on this jumper, so I'm sure it is responsible for the "click".


Thanks. Can't get my head around that. Must be something you have to see in the flesh to understand. Does the fly-back-yoke jumper rotate anticlockwise somehow?


----------



## Silver Hawk (Dec 2, 2003)

Who. Me? said:


> Silver Hawk said:
> 
> 
> > The red arrow points to the fly-back-yoke jumper...and looking at the angles, I don't think this would stop a push of the start/stop button. In fact, I think this is the part that gives the firm "click" when you push the top button. You're actually pushing the fly-back-yoke past this jumper and its spring. Nothing else acts on this jumper, so I'm sure it is responsible for the "click".
> ...


Andy, thanks for making me take a second look at this :wallbash: :lol:. I was almost right but got my buttons and jumpers muddled up....hopefully I now have it correct in diagram below.

Green is what happens when you press the Start button.....and the photo shows the chrono in the running position....so after the start button has been pressed.

Red is what happens when you press the same button again i.e. stop the chrono

It is the Clutch Operating Lever Jumper that gives the "click" on the start/stop and I've circled the point where your have to overcome the resistance (the jumper is also the spring).

It is the Fly-Back-Yoke Jumper that gives the "click" on the reset button. I don't thing this jumper does anything else.


----------



## Who. Me? (Jan 12, 2007)

Ahh, just a click then. The position of the spring on the 'Fly-back yoke jumper' makes it look like it can only rotate counter-clockwise, so it looked to me like it would stop the 'Fly-back yoke' from sliding back when the reset button was pressed.

Thanks Paul, the pictures are a hell of a lot easier to understand than the PDF of the service manual. They have helped to unlock the mystery of what's inside these.


----------



## Silver Hawk (Dec 2, 2003)

Been researching this movement a little more. It seems that ESA sub-contracted the design and manufacture of the chronograph module to Dubois-Depraz --- this company specialises in making bolt-on chronograph modules for the major watch manufacturers and are still around today. A good read can be had here ---> http://www.ablogtowa...ovement-module/ and their webste here ---> http://www.dubois-depraz.ch/

Last three photos concerning this movement. These show the rather complicated chronograph counters with their :



zeroing hearts --- first after the hand post


floating clutch base --- large disc with the three large holes


friction spring --- between the gear wheel and the clutch base


These are new items which is why they are nice and shiny. In the stop and reset positions, the large 3-holed floating discs get pushed up towards their gear wheel and this exerts additional pressure on the friction spring.

The main centre second chronogrpah counter is the one on the right in this photo. The two smaller ones are the minute and hour counters.










In the next 2 photos, you can see the friction spring between the gear and floating clutch base:


----------



## mel (Dec 6, 2006)

Top work as usual Paul, :yes:

Now that's out of the way, I've a pre-production LACO/TIMEX incoming, trying to source a photo, but it has a lightning bolt seconds which really sets off the watch - - should have been carried on to the TIMEX production IMO.

Have you seen LACO's with this before Paul?


----------



## harryblakes7 (Oct 1, 2010)

Excellent post & pictures Paul :thumbsup:


----------



## Silver Hawk (Dec 2, 2003)

Silver Hawk said:


> Having now studied this movement, it seems to me that this is one chronograph that is best left with the chrono function running. The reason I think this is because these sub-wheels are never dis-engaged from the main movement --- when the chrono function is in the "stop" or "reset" position, the hammers-on-the-hearts etc are stopping the sub-dials turning and it is slipping clutches on all three wheels that allow the rest of the movement to carry on running. Clutches will wear out.





Who. Me? said:


> I've wondered about running the Chronograph all the time. When my Speedsonic Lobster arrived back from Bienne it was running and I'd wondered whether that was due to mis-handling in the post.


Andy, I got this bit totally wrong :duh: . It is true that the teeth of the various gears are permanently meshed with each other, but I misunderstood how the clutch on the centre second chronograph wheel worked. In the reset and stop position, the clutch is in operation which means that the chronograph driving wheel is free to rotate on its shaft rather than drive the rest of the chronograph movement via the shaft....in this position, the only thing it drives is the constant second wheel (the top sub dial).

So it is definitely better not to have the chronograph running.


----------



## apm101 (Jun 4, 2011)

Paul, what a super thread! I don't pretend to understand half of it, but fascinating nonetheless.

I rest easier knowing there's a safe pair of hands for my Speedsonic if it goes belly up on the chrono!

Cheers,

Alex.


----------



## Who. Me? (Jan 12, 2007)

Silver Hawk said:


> Silver Hawk said:
> 
> 
> > Having now studied this movement, it seems to me that this is one chronograph that is best left with the chrono function running. The reason I think this is because these sub-wheels are never dis-engaged from the main movement --- when the chrono function is in the "stop" or "reset" position, the hammers-on-the-hearts etc are stopping the sub-dials turning and it is slipping clutches on all three wheels that allow the rest of the movement to carry on running. Clutches will wear out.
> ...


Thanks. I'll stick with monthly 'anti deterioration' runs.


----------



## JoT (Aug 12, 2003)

Well done Paul and a great write-up :yes:


----------

