Service: Omega Seamaster 120 calibre 601

Petter from Sweden sent this Omega in for a service. Someone has glued the bezel to the case, and there is a good reason for that. As I can’t get hold of a replacement bezel, I’m afraid I will have to leave it in place as it is.

The back gasket has dissolved, and left a black mess – so that will need cleaning up, and the movement wants a service. A new crystal won’t hurt, either!

The movement needs a service, indeed! Huge beat error, almost no amplitude, and waves to no end.

I’ve taken the gasket out, but you can see the gunk left behind. The calibre 601 movement is a very clean construction. Hand-winding, no date, simple but lovely looking. The crown wheel core is a bit rusty, but I can clean that up.

The dial is in very good shape – no blemishes whatsoever.

Time to take apart the movement. You can see that I have already removed the balance bottom jewel with its seat for cleaning.

Everything taken apart, and ready for the cleaning machine.

The obligatory new mainspring starts the reassembly.

Top plate back together and ticking. You can see that I’ve tidied up the crown wheel core a bit.

A first rough adjustment on the timegrapher, with the mainspring 1/2 wound. Compare that to the initial image!

Everything on the bottom plate is nice and tidy, too.

The dial and hands go back on.

I case the movement and put a new gasket in.

The case gets a new crystal, and we’re back in business!


11 thoughts on “Service: Omega Seamaster 120 calibre 601

  1. hi, I’m going to be sending the same watch to you for a clean up and service. could you tell me the crystal reference number then I can buy it in advance for you. thank you.

  2. Well done, I love that watch! Please contact me if you have a black SM120 black bezel laying around, I am missing mine. Cheers!

  3. > Someone has glued the bezel to the case, and there is a good reason for that.

    Did I miss what that good reason was..?

  4. Looking great! Can’t wait for it to hit my mailbox and see it for real again … Christian – thanks a lot and it’s been great fun to follow your work!

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