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Omega Cal. 1120 losing time and acting funny...


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Hello All, 

I'm suddenly having some issues with an Omega SMP 2531.80 with a cal. 1120 movement that I own. I think I may have dropped it, or bumped it into something as some point and that would be the cause of this sudden change. You don't remember....you might say? Yeah, stupid I know, but I have a bunch of watches and if something happened and I didn't immediately notice a problem, I just move on, so.........

Anywho, here are the issues I'm having.....

  • It's now losing about 20-25 seconds a day. It used to be spot on.....lost about 1-3 seconds a day.
  • This one is really throwing me.....when the power reserve runs out the second hand consistently stops at 3 seconds after 12. It is not running into another hand.
  • On a timegrapher, I'm having a huge variance between Dial Up (-36) and Dial Down (+15). Yikes!!
  • Amplitude is 235 degrees at best and 200 at worst
  • Power reserve has never been that great.......about 30 hours

So here are the things I'm thinking, but I'm also looking for any input that you guys would like to share. I suppose what I'm really looking for are ideas of things to look for as I disassemble the watch. For starters, I'm pretty sure I have a bent pivot on the balance staff and would be a root cause for the major swing in time keeping. I have no confidence that the mainspring was cleaned and properly re-oiled the last time, or maybe the gear train was not properly cleaned, but I'm definitely losing power somewhere. What's really perplexing me is the second hand stopping at the same spot when the power reserve runs out. The only thing I can think of is some sort of problem with the 4th wheel......that's all I got.

Unfortunately, with all that's going on with this watch, I think it would be cost prohibitive to send this watch to someone for repair. So I'm stepping up to the plate! I have been honing my watch repair skills for a few years now having recently purchased an Ultrasonic and timegrapher. I've mostly worked on pocket watches with some Japanese movements in there. I've gleaned so much information from the collective on here and I can't thank you enough. I am anxious to see what you guys can come up with.

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Probably a shock protection jewel (guessing Incabloc for Omega) that shifted with a shock and didn't reseat correctly. A hairspring hangup would almost certainly have more drastic timing results. That it stops at that specific area on the seconds hand could be a slightly damaged tooth, that normally wouldn't show up but with the distress at the balance might be more sensitive.

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Hello All, 
I'm suddenly having some issues with an Omega SMP 2531.80 with a cal. 1120 movement that I own. I think I may have dropped it, or bumped it into something as some point and that would be the cause of this sudden change. You don't remember....you might say? Yeah, stupid I know, but I have a bunch of watches and if something happened and I didn't immediately notice a problem, I just move on, so.........
Anywho, here are the issues I'm having.....
  • It's now losing about 20-25 seconds a day. It used to be spot on.....lost about 1-3 seconds a day.
  • This one is really throwing me.....when the power reserve runs out the second hand consistently stops at 3 seconds after 12. It is not running into another hand.
  • On a timegrapher, I'm having a huge variance between Dial Up (-36) and Dial Down (+15). Yikes!!
  • Amplitude is 235 degrees at best and 200 at worst
  • Power reserve has never been that great.......about 30 hours
So here are the things I'm thinking, but I'm also looking for any input that you guys would like to share. I suppose what I'm really looking for are ideas of things to look for as I disassemble the watch. For starters, I'm pretty sure I have a bent pivot on the balance staff and would be a root cause for the major swing in time keeping. I have no confidence that the mainspring was cleaned and properly re-oiled the last time, or maybe the gear train was not properly cleaned, but I'm definitely losing power somewhere. What's really perplexing me is the second hand stopping at the same spot when the power reserve runs out. The only thing I can think of is some sort of problem with the 4th wheel......that's all I got.
Unfortunately, with all that's going on with this watch, I think it would be cost prohibitive to send this watch to someone for repair. So I'm stepping up to the plate! I have been honing my watch repair skills for a few years now having recently purchased an Ultrasonic and timegrapher. I've mostly worked on pocket watches with some Japanese movements in there. I've gleaned so much information from the collective on here and I can't thank you enough. I am anxious to see what you guys can come up with.


Howdy, mouse!
If the seconds hand is stopping at the same point, you’ve got some friction in the power of that hand, it’s pinion, wheels or pivots. Could be as simple as something becoming unseated while it was josseled. But it definitely sounds like it could benefit from a break down and cleaning. It would be good practice, too.

You can do this!! Just take pictures during disassembly.

Let us know how it comes out. And if you have any questions during, stop and come back here.


Sent from my iPad using Tapatalk
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Before strip down, I would give it a full manual wind and make a record of how long it runs on bench. Expectedly runs more than 30hrs, the question is how much longer.

 Repeat the same with the movement out of the case, next raise the seconds hand and repeat, repeat by removing the remaining hands and the dial plate, day disk.....continue with min train bridge with seconds hand put back on. You are eliminating possible faults as you strip the movement down. The game is to find the point movement quits stopping at, then you have found the location of the fault. 

This approach is worth mastering and useful particularely for cases when complete strip down is not on the agenda. Fault finding as you strip the movement down makes sense, to strip down, clean reassemble oil and face the fault is the shoot first ask question later stralogy. :lol:

As for amplitude, I always apply diesel fuel or kerosene to escape teeth and observe the little machine fly. This usually eliminates the, suspect bent pivot story.

Best Regards joe

 

 

 

 

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This one of those faults that are not easy to resolve without close inspection. I would first look at the behaviour of the H/Spring is it breathing evenly. It could just be some dust/dirt that has attached to the spring after it was dropped. If not it is about removing from the case and stripping / cleaning and inspecting as you go. 

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9 hours ago, Nucejoe said:

Before strip down, I would give it a full manual wind and make a record of how long it runs on bench. Expectedly runs more than 30hrs, the question is how much longer.

 Repeat the same with the movement out of the case, next raise the seconds hand and repeat, repeat by removing the remaining hands and the dial plate, day disk.....continue with min train bridge with seconds hand put back on. You are eliminating possible faults as you strip the movement down. The game is to find the point movement quits stopping at, then you have found the location of the fault. 

This approach is worth mastering and useful particularely for cases when complete strip down is not on the agenda. Fault finding as you strip the movement down makes sense, to strip down, clean reassemble oil and face the fault is the shoot first ask question later stralogy. :lol:

As for amplitude, I always apply diesel fuel or kerosene to escape teeth and observe the little machine fly. This usually eliminates the, suspect bent pivot story.

Best Regards joe

 

 

 

 

As always, I enjoy reading what the pros suggest. Thanks, Nucejoe! I will guess that a cap jewel is unseated or misaligned. As far as the second hand stopping at 3 seconds, follow the above. A slow process but you will get to learn and master the proper way to find fault.

Regards.

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15 minutes ago, DavidMasters said:

As always, I enjoy reading what the pros suggest. Thanks, Nucejoe! I will guess that a cap jewel is unseated or misaligned. As far as the second hand stopping at 3 seconds, follow the above. A slow process but you will get to learn and master the proper way to find fault.

Regards.

"Sudden" change of performance, points to unseated or misaligned endstone due to unlocked or broken shock spring which tops the checklist and for most part is visual so is very clearly adviced by master Nicklesilver, considering little explanation on amplitude and power reserve, I gathered the relevent discussion is left to students.

Regards joe

 

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Everyone,

Thank you so much for your responses. This is EXACTLY the kind of information and advice I was hoping to get. Nucejoe, I will absolutely follow your recommended due diligence to try and ascertain the issues before full disassembly. This is an area that I have struggled with in the past and is really the reason for starting this thread in the first place. Right now, based on everyone's recommendations, I'm trying to slow down, put a plan together, gather all the necessary materials (such as the exact oils that Omega recommends on their service chart) and take it step by step. I will definitely be updating this post with pics and progress as I process through this repair, but it may be a little bit of time before I'm ready to tackle this completely. Again, thanks for you for your encouragement and support! 

Chris

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  • 1 month later...

UPDATE:  I know it's been a while, but I wanted to give an update to what I've done so far (which isn't much), what I'm seeing, and how I plan to proceed. I also had an oiling question.

So as Nucejoe recommended, I started by running the movement and seeing how long it took for the power reserve to run it's course which was actually just over 48 hours. That's absolutely within spec, so that ended up not being an issue. The second hand was still stopping at 3 seconds after 12. Unfortunately I had a rookie moment, and neglected to pull the crown out to the setting position (3rd) when removing the movement to run the next test. So without pulling the crown all the way out, it's impossible to properly reinsert it! So with that, I was forced to remove the hands, dial, date mechanism, and half the keyless works in order to get the stem back in. In that process, I found out that the stem is bent. I purchased this used, and when I received it the crown barely had the threads to screw down. Thinking a bent stem was related to that and not wanting that to happen again, I purchased a new Omega stem.

After that I was able to run another test and this time the second hand did not stop in the same place it usually did. Huzzah! I ran that test three more times and the second stopped at a different place every time! Success....except, because I had to skip a few tests (e.g. with dial on, dial off, date off and so forth) I don't know EXACTLY what that issue is, but I at least have an idea. 

Next up, the balance. On my inspection, I could not find any obvious faults. The cap stones did not look out of place, unless its very very slight. Wasn't sure how visible a shifted cap stone would look. I have observed that it does not stop its motion in what I would consider a natural way. It stops rather suddenly. I did purchase (in all my many purchases for this project) an etachron key, as well as learned what its for and how to use it. I carefully opened up the regulator pins on the etachron system and removed the stud (I learned this from another video) and removed the balance complete. My initial inspection at 15x did not show any obvious bends or anything like that in the pivots. So I just ordered a USB microscope and will take a closer look. Hopefully the pivots just need to be thoroughly cleaned, but if not, I already have a balance complete I can use (I don't have the skills nor tools to replace a balance staff). I'm hoping it won't come to that. 

Once I removed the balance, and the pallet fork, I ran the gear train to see how that looked. Again, what I'm seeing is that it doesn't release power in a smooth natural way. It gets choppy at the end of the run where it will stop-go-stop-go and then finally stop. If you shake it a little bit it will go just a little bit more. When I received this watch a few years ago, I was told it was serviced and was given a service record, but on my inspection, the parts are not nearly as clean as I would like them. I have found residue on the bridges and rotor, and the gears do not look as clean as I would hope. So I don't know exactly what was done, but I'm not confident that all my pivots are as clean as they need to be. Or that it was properly oiled. 

So that's it...that's where I'm at right now. I plan to disassemble bit by bit, and inspect everything (endshake, sideshake and close microscope inspection) so I can hopefully fault find. I'm sorry this was so long, thank you for reading if you got all the way through. One question I did have concerns oiling. I've watched Marc's video on servicing the Omega 2500 (which from what I understand is exactly like the 1120, but with the co-axil) and I've noticed that he oils the winding pinion, sliding pinion, and stem with Moebius 9501 (cause it's blue) and not the recommended HP-1300 (which is red) from the technical sheets. I do not have the 9501, I purchased 9504 instead cause that was a change that was made on the technical sheets. So which should I use? Is there a reason that the HP-1300 is not used?

Ok, again thank you so much for your input. I didn't add pics, cause I didn't think there was anything to really show just yet. It looks like what you'd expect.

Edited by mousekar
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If the seconds hand stops at the same point each time, then my guess would be that the sweep seconds wheel could be suspect. It could also stop in a pattern if there is an issue with how it meshes with the adjacent wheels.

Id suggest you take out the sweep seconds wheel and inspect the teeth. Also see if it is straight where the seconds hand attaches. They occasionally get slightly bent by ham-fisted watchmakers when hand fitting. 

For the keyless works lubricants, don’t get too hung up over whether a grease or a heavy oil is used. Both will work fine. I have a preference for grease myself here as it’s easier to apply in some respects. The correct oiling of the main wheel train bearings is more important.

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Also, regarding your original post, bent balance pivots are just not common on incabloc balance settings, but still possible. If it was a non-antishock watch then it would be reasonable to suggest, along with checking for a “mushroomed” or broken pivot. Occasionally you’ll come across an antishock balance setting which is fussy about seating correctly which may bind the pivot. Release the spring on the balance cock without removing the jewels and see how the amplitude responds. If it increases then it’s obvious that there’s possibly an issue with either or both settings. 

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  • 2 weeks later...

Thank you so much rodabod! The majority of my experience has been spent on pocket watches without the anti-shock where bent pivots on the balance are rather common place and it's just the first place my head goes. Inspecting the balance pivots closely I'm not seeing any noticeable issues. 

I purchased USB microscope and closely inspected the 3rd and 4th wheels. I'll attach some pics so you guys can see what I'm seeing. It looks to me like some of the teeth are pretty well worn on both wheels and consequently I'll be replacing both of them. I think this could also explain why the second hand was stoping the way that it was. Not to mention that they're not clean at all.

 

 

 

 

 

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Edited by mousekar
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Hi, I don,t think this wear on gear teeth, would cause any considerable  issue with your watch, gear replacement is unneccesary. 

Sudden Changes are mostly due to the type of faults already mentioned by Nickelsilver.  Will you show staff jewels and endstones(cleaned) .

Good clean and lube of the selfwinder module and barrel is likely to remedy poor torque delivered to the barrel and will enhance the power reserve.  

 

 

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  • 2 weeks later...

sigh.....

luckily, I already purchased a replacement. I know this can be fixed with some patience and fine point tweezers, but right now I just want the watch running again. I'll use this as practice at some point, but for now, it's getting replaced.

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If it was me I would first just massage the spring at the 07:00 o'clock position. You might be lucky in thats all thats need moving. 

What I call the terminal curve (Blue) is critical that it has a uniform curve in relation to the curve of the  main body of the spring. If not when regulating the spring it will go out of centre. 

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