Hello, I have a 2531.80 Seamaster I acquired within the last year. Previous owner included receipt for full overhaul service shortly before my ownership. Service was done at a local watchmaker and promised -1s a day and 300 amplitude on receipt. However, I've measured the timekeeping recently and I'm not sure if it's a sign of a needed service. The amplitude was always under 250 ever since I received it, it didn't matter as it ran fine for me so I kept it, but I've started to get concerned as it seems to have more variance, and on average wear it loses time. I would like your opinion. Should I send in for a service? Or keep it going a few more years as is? Thanks Dial up: +4 seconds a day. 235 amplitude. 0.1 beat error. Dial down: -7 seconds a day. 249 amplitude. 0.0 beat error. I'm also keeping track of power reserve and see how far I come to the 44 hours on this caliber 1120. I should know by Friday. I did wind the watch manually, and didn't feel like I wound it too much and yet I could feel the main spring slipping. I'm wondering if there is a problem with main spring/barrel.
I'm sorry that I can't be more helpful from the technical side of things and I hope that someone with more expertise in this area will chime in soon. However, my question for you is this: What is your "real world" experience with this watch? What is the average daily rate that you're noticing based on your wearing habits? If it's within -4 to +6 seconds a day, then it would be considered "within spec" by Omega and most people. In that case, I'd not worry too much and just enjoy your watch. I've got the midsize SMP with the same Cal 1120 movement and it's currently running at just over +3 seconds a day, which I'm happy with. I know that some people may be more demanding and want better accuracy. Or they prefer a watch to be running a bit fast rather than a bit slow. It all comes down to personal preference. I hope you get the answers you seek soon. Cheers!
Cal. 1120 is from the mid 1990's. What do you expect from it? You don't even know, what the previous owner paid for the whatever called Service.... Be happy and enjoy your watch.
How much on average is your watch gaining/losing per day? When I had mine serviced the amplitude was circa 270. I wouldn't worry about amplitude just overall daily accuracy
Assuming you’ve set the lift angle correctly, not always a given, that is a very low amplitude for a fully wound 1120, which is in essence a 2892-A2. As da man above says, it’s time for a proper service, maybe last time he kept the old mainspring or just didn’t do a very good job. Are you suggesting the 1120 is inferior to the more modern offerings? That isn’t my experience really. The 2500 and 8806 might look way better on paper but they all do a similar job when healthy. Indeed it could be said the 1120 was superior to the first 2500 offerings in A and B spec