I recently found an uncatalogued model, which is always fun to find. Based on some detective sleuthing I'm very confident it's a legitimate model, so I'll walk you through my thought process.
As received it was a little dirty and the crystal was crazed with fine cracks internally. The 12 and 6 markers are larger rectangles and have the numbers on them.
Here's a better shot of the crazing. This crystal will need to be replaced but it's the wrong style so it would have been replaced anyway.
The number on the case back is 985369. This would tell me that it's a 1969 model. The catalog available on line is a 1968/69 version so it wouldn't have a 1969-released model. Based on the online forums, this is the first 985369 to be found. I didn't take a photo of the inside of the case back but it has the proper Hamilton Watch Co Lancaster PA markings and a unique serial number for this watch.
Inside the case is a 17 jewel 674 movement. This manual wind version of the automatic 694 is used in the Dateline S series. There are a handful of S-models and I suspect this is one of the last ones.
All of the parts are disassembled and ultrasonically cleaned.
The reassembled movement is ticking away with good motion. Let's see what the timer has to say.
It's running a little fast and the beat error of 2.3ms is on the high side. Both are very easy to adjust. The amplitude of 193 degrees is a little low. I'd prefer to see it well over 200 but I haven't wound this watch up all the way.
First I'll adjust the beat error by moving the location of the hairspring stud on the balance cock. It doesn't get better than 0.0 - that means the balance swings equally from one side to the other.
Now I can lower the beat rate by adjusting the regulator pins relative to the hair spring stud.
Winding the watch up more fully, the amplitude increased to an acceptable 234 degrees.
Putting the hands back on requires advancing the time until the date changes. Then it's midnight and the hands can be position accordingly. Notice I replaced the lume on the hands so they will glow in the dark again.
This mystery Dateline S-something turned out great. With a proper crystal it really looks fantastic and it runs as good as it looks!
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