zOwie Omega Discussion Forum

I received my watch (2531.80) as a gift last month. It has been gaining time ever since. I watched it for a week and gain was around 50 seconds (7 days). This was further observed to gain most of the time when wearing it. Over night, it would gain about 2-3 seconds, but wearing during the day (7AM-10PM) the gain was an additional 5 seconds. This was pretty unacceptable to me, especially for a new product. Moreover, it was certainly out of specifications. The local dealer requested the watch for an unspecified amount of time for adjustment. Actually, I was told, a period of 3-4 weeks would be required for repair. Again, not acceptable.

I started reading and looking on various web sites for information on the adjustment of mechanical watches. As I said before, I did not think it was a major project. It turned out to be perfectly simple, well within the range of my limited talents and I would suggest a wonderful adjunct to those who like to fiddle with watches that are not really tuned properly. I have never before worked on a watch before in my life, except to change a quartz battery in my Seiko that I purchased in 1979. That watch still keeps great time (within a second a month)!

First, I made several assumptions. I did not adjust the winding of the watch at all. I wanted it to be running in as much a steady state as I could. Secondly, I assumed each day the watch would sit for at least 6-8 hrs for sleep and rest. Lastly, I assumed this adjustment could be done without a timing machine since the watch was keeping fairly regular time, I suspected no abnormal wear and felt the parts would not require replacement.

Optics:

I obtained 3.6X @ 350mm working distance Zeiss loupes, a 20 Diopter hand lens and 5X/7X jewelers magnifiers for my glasses. I also have a 2X "optivisor" with a halogen light source. The loupes are wonderful for this work, the optivisor is marginal.

Fine Instruments:

Dumont 5A Jewelers forceps
Bergeon Watchmaker Screwdriver 0.8 mm

Miscelaneous:

L-G Waterproof case wrench, using the CWR-600.01 cover with holes. These are very fine round posts that fit into round holes but they are about 0.4mm and much too small to directly open the case of the Seamaster.

Omega Case opening set with the 3236 case block and the large size 5-pin case back removal tool.

Modifications: The Omega case back removal tool is manufactured to have a 5/16 in or 8mm square steel reinforced receptacle for a case opening press. Since I do not have the press to open the watch directly (cost was $300), I carefully marked the L-G case opening pins with ink and pressed them directly on the top of the Omega tool, making a template to drill against. Using my hand drill (I was too lazy to go to my friend's house for a drill press) and the smallest size drill in my Sears set, three small holes less than 1 mm in size were made in the tool, corresponding to the insertion points from the L-G case opening pins. The case opening wrench was then placed against the tool, tightened and it fit like a glove.

Procedure to adjust the watch:

1. Remove a link pin from the band. I used an A&F tool 189.810 which simply pushes the pin from one side of the band to the other. It takes seconds to remove and replace the pins.

2. Open the watch up and place it in the Omega case holder.

3. Place the Omega 5 pin tool into the back of the watch. Position the L-G case wrench into the modified holes and press down on the case firmly.

4. Turn the case back slowly counter clockwise at least 1/3 turn before removing the wrench and continuing to unscrew the back by hand.

5. Use the Dumont forceps to gently remove the case back. I tried not to touch my fingerprints on any internal part of the watch.

6. Remove the antimagnetic case from the action. This is loosely fit and lifts off.

7. Rotate the self-winding wheel with the Dumont forcep to expose the adjustment mechanism.

8. My watch was set up with the screw in the "Center" position. Lets call this "12 o'clock". To speed up the watch turn the screw counter clockwise. I turned mine clockwise to slow it down. This is clearly marked with a "-" and a "+". After several adjustments and trials, I determined that my watch had a rough corresponding screw position that related to the number of seconds it needed adjustment. It seemed that my watch needed between 1 and 2 "minutes" of turning for each "second" daily retarding. In other words, in order to tune out the 7-8 seconds of advancement the screw turned so that it was about at the 2 o'clock position. I hope this is clear.

9. Replace the antimagnetic cover.

10. Replace the case and tighten to the original position.

11. Restore the link pin.

12. Reset the watch to your computer or WWV source.

The first time I did this, it took about 15 minutes. Later adjustments reqired much less time. I continue to wear the watch and plan to double check the watch using a bonafide timing machine. However, I am more than satisfied as two adjustment tuned down the time advancement to 1-2 seconds per day. Based on my experience, since I do the same activity each day and have the same schedule, I should be able to tune out virtually all the time gained by the mechanism and neutralize the watch.

I really like the watch enough to do this. If I had a choice, I probably would have purchased the quartz model and used that as my daily replacement for my aging Seiko. After 20+ years on the job that watch was getting pretty tired. I didn't want to look like an ingrate and return the gift.

Probably going to get a lot of flack for this posting, so in closing I want to add. I enjoy working on intricate small items that require tedious attention to detail. I like tools and using new tooling. This work seemed quite natural to do and I feel it will allow the watch to keep very nice time, without any great disappointment regardless of the chronometer certification.

For those who might want to try this at home, good luck!