This Omega was sent in by Rak for a service. It’s working, but the amplitude is quite feeble and under 200, and the beat error is 2.1 ms. Time for a service.

Great case, great dial, great watch! You can’t go wrong with a vintage Seamaster.

The movement looks good. The case back gasket is pretty old – it’s been compressed and staying flat in some areas. I always put in a new gasket, anyway.

Lovely dial in very good condition.

Day and date wheels.

Bottom plate without the day and date wheels.

The top plate without the auto winder.

The gear train exposed.

Mainspring in barrel.

For cleaning, I put all the small parts (screws, jewels, etc.) into a cleaning basket.

Everything cleaned, rinsed and dried and ready for reassembly.

As usual, I start off by putting the balance jewel assemblies back together and oiling them.

Then the barrel and wheel bridges are mounted, and I slightly wind the mainspring to check the wheels for wobbles and to see if everything turns freely. After oiling, I expect the escape wheel to slightly recoil when the mainspring has run out.

The balance starts swinging as soon as it’s dropped in.

With the mainspring only slightly wound, I get a great amplitude, and I adjust the beat error to 0ms. I won’t finely adjust the beat rate yet as I will let the movement settle for a day before doing that.

After having put the bottom plate assembly back in, I adjust the date wheel so it changes simultaneously with the day wheel, then I mount the dial and hands.

Ready for casing.

What a beauty!

The old case back gasket has seen a couple of decades – it’s completely brittle and breaks up as I remove it.