This A4 sheet is dated October 1985. The parts descriptions are in French, English, Spanish, German & Italian ( I've guessed it's Spanish !)
On this web page I refer only to 861 & 863 movements. BUT I assume that most of this information is just as relevent to the 1861 & 1863 movements.
One of the most questions posed most often in various Omega Forums is :-
"What is the difference between the 861 movement and the 863 movement ?"
The simple answer is the finish & ( most of the ) 861 movements have a plastic brake ( part number 1726 - Blocking lever - below), whereas on the 863 it is metal.
I recently came across this A4 sheet (printed on both sides) which lists the 863 parts that differ from the 861.
So for any of you really sad WIS's out there ( yes, you can put me in that corner ).... the definitive answer is there are 22 parts that are different and at least 13 screws. I say at least 13 screws because this leaflet doesn't actually say how many of each screw is used in the movement.
So having now searched the internet for hours & finally found the definitive answer, you can now sleep in peace tonight !
Click on either of the pages below for a larger (approx 60 or 130 KB) version.
I don't think Omega will have a problem with me reproducing these pages on the internet. They are good enough quality that they can be used, but not so good that people can copy, print & sell them as originals.
I have written this page to share the limited knowledge & information I have. Please don't abuse me, my work or other peoples pictures. It's not a nice thing to do !
Finally, It pisses me off that I have to write a disclaimer like this !