Sellita SW 220 Hack issue

[Kappa505]

This watch will run great for a few months and then stop suddenly. I believe I have narrowed it down to the hack mechanism but am not positive that's what it is or even what to do if it is the problem. When fully assembled I am making sure the hack is engaged with the groove of the sliding pinion. What are some potential causes of this nonsense?

[nevenbekriev]

Hi there,

Demonstrated in the video only shows that the movement will not (auto)start when the hack lever is returned back. This can be due to different things (bad condition of the movement, wrong zero position of balance(bear error)...), but will not explain sudden stops at all, if the hack function has not been engaged. You can remove the hack lever if You need to be sure.

[Knebo]

What you are showing is the correct functioning of the hacking spring.

But @nevenbekriev correctly points out that a healthy movement should restart automatically when the hacking spring is slid back. Do you have a timegrapher to check the beat error (and also amplitude to get an idea of overall movement "health")?

 

PS: In the video, are you restarting the movement by pushing on the escape wheel with your tweezers? Looks a bit dangerous to me - could maybe damage the pallet fork/jewels if done too hard. Would a gentle shacking of the movement also restart it (indicating that beat error could be too high).

 

ALSO, could you describe in more detail the pattern of the watch stopping?

- It stops regularly (i.e. every day or every couple of days) after it has been running well for months?

- Or it stops very rarely, only every few months (so a pattern you observed over years)?

 

---> Are you sure the watch is wound when it stops? It could be that the automatic winding is worn and winds inefficiently. Then it can happen that it'll just run out of power (if you don't manually wind it).

 

Edited June 6, 2024 by Knebo

[Kappa505]

I will post a pic or video of the time grapher when I get off work. When I first bought this watch it ran "ok" +8seconds/day for probably 6 weeks. Then it stopped suddenly at night tapping, shaking, manipulation of the crown wouldn't change anything. After that I started on a service and as soon as I had the crown out and the movement holder screws out it started again so I stopped the service and put every back. It worked well again for another few weeks and then it stopped (I knew it was going to as I hadn't done anything to fix it in the first place) again. So I did a full cleaning and service. It worked again for probably another month after that at +4 seconds/day and then stopped again. Beat error was never higher than .3ms either time I tested it. So I took it apart again and started to assemble. During installation of the sliding pinion I was checking to see if the operation of the hack was functional and noticed that the balance didn't not start again on its own. I will post a video of the time grapher as the movement stands tonight when I get off work. 

[Knebo]

Interesting mystery. We all like mysteries (if they get solved).

 

How about this? 

3 hours ago, Knebo said:

---> Are you sure the watch is wound when it stops? It could be that the automatic winding is worn and winds inefficiently. Then it can happen that it'll just run out of power (if you don't manually wind it).

 

[Kappa505]

4 hours ago, Knebo said:

Interesting mystery. We all like mysteries (if they get solved).

 

How about this? 

 

Yes, I believe its wound. I believe someone else was inside this watch before me. Which leads me to another question which is how do you know if a part looks correct if you have no experience with a certain movement before. How would I be able to tell if the hacking lever was bent or not without prior experience? This would go with any part for that matter. The keyless works have many parts with many bends in them. Could balance stones being placed upside down cause this issue?

[Knebo]

15 minutes ago, Kappa505 said:

Which leads me to another question which is how do you know if a part looks correct if you have no experience with a certain movement

First, have a look at the parts list in the official documentation:

https://www.sellita.ch/scripts/calibres/images/Brochure_technique-SW220-1_28.pdf

Here's also a "real" picture of the parts (this is a SW200, but it's the same except day of the week) 

[Kappa505]

8 minutes ago, Knebo said:

First, have a look at the parts list in the official documentation:

https://www.sellita.ch/scripts/calibres/images/Brochure_technique-SW220-1_28.pdf

Here's also a "real" picture of the parts (this is a SW200, but it's the same except day of the week) 

I used the service manual along with Mark's video on the ETA equivalent that he has on youtube to do the service. 

[Knebo]

24 minutes ago, Kappa505 said:

I used the service manual along with Mark's video on the ETA equivalent that he has on youtube to do the service. 

I believe you that you put it together correctly. 

I was only responding to your doubts/need about the correct shapes of parts. 

If the part drawings in the manual and my picture don't provide enough detail, you can search for individual parts on Google or eBay. You'll easily find close up pictures of each part (also maybe giving you a better idea of the 3-dimensional aspects). 

Edited June 6, 2024 by Knebo

[RichardHarris123]

I agree with @nevenbekriev, remove the hacking mechanism, at least it will rule out one thing. 

[Knebo]

18 minutes ago, RichardHarris123 said:

I agree with @nevenbekriev, remove the hacking mechanism, at least it will rule out one thing. 

Yes, that makes sense. No harm in trying that before anything else. 

[Kappa505]

1 hour ago, Knebo said:

Yes, that makes sense. No harm in trying that before anything else. 

I am not certain that it is assembled correctly. I will remove the hack and see what that changes/doesnt change. Thanks for the advice guys.

[Kappa505]

Ok the time grapher for a few positions is as follows. 

Dial down first

Dial up second

Crown up third

Crown down fourth 

[ColdWind]

Are those the highest amplitude value you get with the movement? If so it's deffinitely a problem cause I would expect atleast 280+ amplitude horizontal positions fully wound. Usually I get 300+ amplitude easily with modern ETA or Sellita. The hack wouldn't be a reason for low amplitude.

[JohnR725]

On 6/6/2024 at 9:55 AM, Kappa505 said:

Could balance stones being placed upside down cause this issue?

yes the end stones on the balance are flat on one side curved on the other. So yes curves side out unless you would like to reduce your end shake and have issues like you're having. Oh and minor technical problem the lift angles 50° according to the tech sheet.

8 hours ago, Kappa505 said:

Ok the time grapher for a few positions is as follows. 

Dial down first

Dial up second

Crown up third

Crown down fourth 

you dropped off a specification like the watch was fully wound up or its 24 hours later? So dial-up and dial down should be as close to identical as possible you have 221 and 215 maybe it's okay but it seems like they should be a little closer. Then as soon as you go to the crown positions dropping below 200.this is definitely a problem watch companies don't care about the maximum amplitude sort of in not supposed to go above 315° on this watch but at the end of 24 hours in the 6H  which is basically the 6 o'clock is up at the end of 24 hours it cannot go below 200° and basically all of your crown positions are unacceptable. Here is what the specifications are

4 hours ago, ColdWind said:

Are those the highest amplitude value you get with the movement? If so it's deffinitely a problem cause I would expect atleast 280+ amplitude horizontal positions fully wound. Usually I get 300+ amplitude easily with modern ETA or Sellita. The hack wouldn't be a reason for low amplitude.

you will note that watch companies do not get obsessed with amplitudes like they do in this group. They only get obsessed with amplitudes at 24 hours for which this watch is unacceptable. although I'm assuming and I hate to do that that this watch is probably fully wound up and it 24 hours probably a miracle if the watch runs at all.

[Kappa505]

Could a damaged setting lever spring cause the stoppage? If the spring has been deformed by using sharp tweezers to remove the crown could it allow the hack to stop the balance? I need to get the movement reassembled with the hack removed. 

[Knebo]

As others have said, amplitude is way too low (assuming this is at full wind). You need to deduct another 10° or so because of the wrong lift angle (as John said, it's 50, not 52). I would rather think that the overall movement needs a full service. I'm less convinced by the hack spring (and setting lever) hypothesis. But it's worth a try to reassemble without the hack spring. Why not.

[Kappa505]

Ok. After many months following this initial post I believe I found the issues that were causing the problem. I found that I had indeed installed a balance jewel upside down along with the winding intermediate wheel. After resolving these issues the watch is running for almost 9 months really well without stopping for no reason.