ETA 2789 regulator--no room to adjust

[Levine98]

Hi,

I'm servicing a mid-1970s ETA 2789. One problem I'm having is in order to get the sec/day to +/- I need to move the regulator arm all the way to the + side.

While I do have it running well at this position (+/- 10 sec/day multiple positions, 0.0ms beat error, 255 du/dd 220 cu/cd etc..), there is no room left for any further adjustment.

I don't see any way to adjust the balance wheel--what can I do besides leave it as is?

THanks in advance--Jay

Edited Sunday at 11:01 PM by Levine98
grammar

[JohnR725]

What you have is considered a two-piece regulating system. Move the regulating arm back to zero.. Then move the  hairspring pins  to the suitable location and then fine adjust with the regulating arm. It's a two-piece system.

Often times when you look at the parts list ill actually show two separate pieces layered together  this time it does not but we have to look at the fine print

So the picture gives the impression that it's a one piece regulator.. But the text tells a different story

 

So with a system like this you can roughly adjust the regulating pins then do the fine adjustment with the arm..

[rjenkinsgb]

I'm not at all sure, but it appear the second "adjustment" on that movement is the spring anchor and would change beat error rather than timing?

If so, It would allow the regulator to be re-adjusted but would also need the hairspring rotating on the balance to get the beat error setting again?

 

 

[JohnR725]

The image below is from a different watch it's using the etachron system of principles exactly the same three separate components layered on top of each other each one is independently adjustable sort of. Reason I make the reference sort of is classically if you move one like if you move the beat L chains the regulation so you have to cut I go back and forth and moving everything. Which is why suggest putting the regulating arm back in the middle and moving the regulating pins and the stud moving them until you're reasonably close and then finish up with the regulating.

 

 

19 minutes ago, rjenkinsgb said:

I'm not at all sure, but it appear the second "adjustment" on that movement is the spring anchor and would change beat error rather than timing?

If so, It would allow the regulator to be re-adjusted but would also need the hairspring rotating on the balance to get the beat error setting again?

Three adjustments unfortunately part 303/2 shows up as one part but it's actually two separate parts the arm is independently movable to the regulator pins. Part number 375 is for holding the stud that's what you used to adjust the beat.

Although it's conceivable as it shows is one part it might actually be one part but it's still supposed to be independently adjustable.

 

The little fuzzy but I found a picture online if you look you'll see that each of the three components are separate components layered together.

 

 

[nickelsilver]

The tech info is confusing, but I have seen these where the regulator is one piece and it is possible to run out of adjustment. You can rotate the hairspring on the staff a bit counter-clockwise, which will mean you have to rotate the stud holder counter-clockwise to bring it back in beat; this will give you  a few more degrees of adjustment.

[Levine98]

9 hours ago, JohnR725 said:

What you have is considered a two-piece regulating system. Move the regulating arm back to zero.. Then move the  hairspring pins  to the suitable location and then fine adjust with the regulating arm. It's a two-piece system.

Often times when you look at the parts list ill actually show two separate pieces layered together  this time it does not but we have to look at the fine print

So the picture gives the impression that it's a one piece regulator.. But the text tells a different story

 

So with a system like this you can roughly adjust the regulating pins then do the fine adjustment with the arm..

Yes, unfortunatly even though there is a two piece system there is a limit to how far you can adjust the requlator pins before they bump into the fine adjustment arm. I've tried to push the regulator armature further but it just pushes the fine adjustment arm.

3 hours ago, nickelsilver said:

The tech info is confusing, but I have seen these where the regulator is one piece and it is possible to run out of adjustment. You can rotate the hairspring on the staff a bit counter-clockwise, which will mean you have to rotate the stud holder counter-clockwise to bring it back in beat; this will give you  a few more degrees of adjustment.

I will try that, thanks.

5 hours ago, JohnR725 said:

The image below is from a different watch it's using the etachron system of principles exactly the same three separate components layered on top of each other each one is independently adjustable sort of. Reason I make the reference sort of is classically if you move one like if you move the beat L chains the regulation so you have to cut I go back and forth and moving everything. Which is why suggest putting the regulating arm back in the middle and moving the regulating pins and the stud moving them until you're reasonably close and then finish up with the regulating.

 

 

Three adjustments unfortunately part 303/2 shows up as one part but it's actually two separate parts the arm is independently movable to the regulator pins. Part number 375 is for holding the stud that's what you used to adjust the beat.

Although it's conceivable as it shows is one part it might actually be one part but it's still supposed to be independently adjustable.

 

The little fuzzy but I found a picture online if you look you'll see that each of the three components are separate components layered together.

They are seperate, however the fine arm adjustment still limits how far you can push the regulator pins to the left/right.  You can adjust the regulator pins about 45 deg before bumping into the fine arm and then it starts moving with the requlator arm. 

 

They are seperate, however the fine arm adjustment still limits how far you can push the regulator pins to the left/right.  You can adjust the regulator pins about 45 deg before bumping into the fine arm and then it starts moving with the requlator arm. 

Edited Monday at 10:11 AM by Levine98

[nevenbekriev]

As @Nickelsilver says, turn the collet on the staff anticlockwice so the studd carrier will move anticlockwice too, in oorder to keep the beat error 0. This will free space for the regulator to be able to go furder on the spring (away from the studd carrier)

[Levine98]

Well, thanks everyone who pitched in on this. I was able to recover a smattering of adjustbility but overall not a lot of improvement re: there simply isn't that much room on the beat error armature to go much further to the left (if you're looking down on the balance as in my picture. 

While this is frustrating, the movement itself is running well (+270 amp du/dd with 0-5 s/d at 0-3ms beat error dd/du respectively). Similar for cu/cd and cl/cr with just -30-40 amp from du/dd.

I'm thinking the hairspring might not be the correct length, but I lack the skills to shorten it. I could also purchase a NOS balance complete for $25, but since the movement is running strong I'll probably leave it be and move on (I'm a hobbyest, so this watch will just go back onto eBay once I finish restoring the case).

Thanks again--Jay

[steve1811uk]

Refer to the attached. You can hold A while moving B.

Move A to the middle, B will also move anticlockwise. Hold your tweezers against A from the left so that A cannot move to the left. While holding A stationary, move B clockwise with another set of tweezers. B will move while A stays in the middle. Then use A to fine tune.

 

Hope that helps.

 

 

[nickelsilver]

18 hours ago, Levine98 said:

Well, thanks everyone who pitched in on this. I was able to recover a smattering of adjustbility but overall not a lot of improvement re: there simply isn't that much room on the beat error armature to go much further to the left (if you're looking down on the balance as in my picture. 

While this is frustrating, the movement itself is running well (+270 amp du/dd with 0-5 s/d at 0-3ms beat error dd/du respectively). Similar for cu/cd and cl/cr with just -30-40 amp from du/dd.

I'm thinking the hairspring might not be the correct length, but I lack the skills to shorten it. I could also purchase a NOS balance complete for $25, but since the movement is running strong I'll probably leave it be and move on (I'm a hobbyest, so this watch will just go back onto eBay once I finish restoring the case).

Thanks again--Jay

How does the gap of the regulator pin look? It should be fairly close, like 1.5 to two hairspring thicknesses (as a rule of thumb). Just a little more gap can cause a large drop in rate.

[Levine98]

On 6/25/2024 at 10:58 AM, steve1811uk said:

Refer to the attached. You can hold A while moving B.

Move A to the middle, B will also move anticlockwise. Hold your tweezers against A from the left so that A cannot move to the left. While holding A stationary, move B clockwise with another set of tweezers. B will move while A stays in the middle. Then use A to fine tune.

 

Hope that helps.

 

 

Thanks. I tried this. There is a point when B bumps up against the bottom of A. If I continue to force B, it then tries to go under A risking A being pushed off the balance.

In short, there appears to be a limit to how much swing B can achieve and best of my ability I’ve hit this limit.

On 6/25/2024 at 12:09 PM, nickelsilver said:

How does the gap of the regulator pin look? It should be fairly close, like 1.5 to two hairspring thicknesses (as a rule of thumb). Just a little more gap can cause a large drop in rate.

Lookd fine when I checked it, but I’ll put it under the scope again to be sure. Thanks

[nevenbekriev]

OK, looks like the only reasonable option left is to shorten the hairspring a little. Is it pinned to the stud or it is glued?

[Levine98]

26 minutes ago, nevenbekriev said:

OK, looks like the only reasonable option left is to shorten the hairspring a little. Is it pinned to the stud or it is glued?

Pinned.

Like I said, not comfortable doing that level of horological brain surgery at this stage of my learning journey (I’m three years in).

I’m really happy to have diagnosed the problem and gotten the movement to run very solid at this point (after having disassembled and reassembled the balance about 6 times to get it as far as it would go).  At this pointI the movement timing numbers in all six positions are very solid and a smidgen of adjust is still left.       

Besides if I muck it up, which I figure is better than 50/50, I’ll have to purchase a balance complete since I don’t keep any spares on hand.