Omega Semaster 200 Automatic - movement

This may sound like a frivolous question perhaps, but if what is there is working, why bother? The 1111 and 1109 are very very closely related to their ETA equivalents and differ mostly in finishing. I get that it may be a labour of love but looking at the state of the bezel and crystal there, it will never be a minter and even it if were, its not cost effective to restore this. Bezels for instance are no longer available anywhere so the Omega recommended fix for damage like you see there is a new case! To put that fully back to stock will cost more than its worth.

Ok. I’ve been down this road with a Pre-Bond a couple of times myself so I wish you luck. The crystal won’t be a problem, those are still around. I’ll be very surprised if he can find a nice genuine bezel though. Aftermarket inserts are easy to source (but though look different) but they stopped supplying genuine bezels over a decade ago.

As for the movement. Keep an eye on EBay and one will turn up. Look for a damaged 1980s Omega donor at a cheap price perhaps. Or a loose movement from a scrapped gold model. Personally I’d leave the 2892 movement as it is. You can never make it fully original since the movement it was born with is seemingly long gone and what you have is functionally the same. Which Omega movement is correct? Most auto PreBonds I have seen have had the 1111, the 1109 I think was a later development which fixed a specific winding issue and wasn’t around for much of the production run. I’m not certain but that’s my feeling.

What does the back look like? In the absence of a serial number you can date these roughly from the back design. Plain text only 2 piece came first then there was a decorated 2 piece then decorated one piece back. Note your has early hands but a later crown so might not be one of the very first. Oh and lastly, are there any markings on the interior of the back? The quartz models had the serial ink printed there but I’m not sure if they bothered with the autos, probably not since the serial was already on the movement. The case number change 3 times starting with 1042. That can indicate age too.

Also, be aware that the early Omega movements actually had eta stamped on the main plate (from what I remember) so are you sure it’s not the original movement? Photos?

This is a valid point but the rotor has Omega stamped clearly on the 1111, but not on the ETA so it's pretty obvious if that at least has been swapped. Also presumably he has looked for a serial number and not found one. OP I think it best if you do post a pic to put it to bed.