Watch Service: Oris Aquis Date. Cal Sellita SW200-1.

Oris service

Nigel sent me his Oris watch as it wasn’t winding anymore, at 6 years old its also due a service. It houses the Sellia SW200-1, pretty much a direct clone of the ETA 2824. Sellita are becoming more popular with many brands, mainly due to their availability over ETA.

Seillta were a major assembler for ETA movements before The Swatch Group bought ETA – this was the beginning of the end of the situation as Swatch decided it would no longer out source this work. At the same time Swatch made the decision to stop supplying other brands with ETA movements, as such Sellita saw an opportunity. Already being set up to build the ETA 2824, and with the patent now expired on the ETA version, Sellita would produce their own version of the movement, enter the Sellita SW200-1.

Oris service

Case back and automatic device removed, showing the Sellita movement. If you are familiar with the ETA 2824, the similarities are instantly recognisable.

Oris service

The reason for the watch not winding is instantly obvious, damaged teeth on the ratchet wheel. In the black circle in the picture above, the broken teeth can be clearly seen, as such the crown wheel that engages with the ratchet wheel in order to wind the watch just slips against the broken teeth. This part will certainly be replaced during the service. It is actually quite a common fault with the Sellita version, I do see it on the ETA, but no way near as frequently. Automatic watches should be manually wound before being worn to ensure there is enough power in the watch to keep it running, unfortunately its this manual winding that over time causes the damage to occur.

Oris aquis date service

Movement removed from the case, the dial and hands are prepped for removal.

Oris aquis date service

Dial side of the watch, again to all intents and purposes it looks like an ETA 2824.

Oris aquis date service

This side is disassembled as far as I will go for the moment, before turning over and beginning disassembly of the top side.

Oris aquis date service

Ratchet and crown wheels removed revealing dirt and old oil underneath, this will all of course be removed first by hand and then properly cleaned to remove any trace once it has its cycle through the cleaning machine.

Sellita sw200-1 service

Barrel bridge removed, particles from the broken teeth on the ratchet wheel can be seen on top of the barrel.

Sellita sw200-1 service

Removing the pallet fork.

Sellita sw200-1 service

Removing the last few parts of the keyless works before the movement is put through the cleaning machine to remove all old oil, dirt and any particles from the broken ratchet wheel teeth.

Sellita sw200-1 service

After cleaning I begin rebuilding and re oiling the movement, perfectly clean I now oil it to the exact specifications that Sellita call for, the barrel and barrel bridge are back in place along with parts of the keyless works.

Sellita sw200-1 service

Train wheels back in place.

Sellita sw200-1 service

The movement is now at a point where it will run, a new ratchet wheel has also been fitted so it can again be manually wound.

Sellita sw200-1 service

Dial side almost complete.

Sellita sw200-1 service

The classic red Oris rotor from the automatic device – its this that rotates with wrist movement to wind the mainspring through a set of gears and power the watch.

Sellita sw200-1 service

Watch almost complete, dial re fitted, the hands will be next.

Sellita sw200-1 service

The completed watch, it will go through the usual tests before being returned to the customer. Overall its a very nice watch and straight forward to work on, being a Sellita, the parts are also readily available and reasonably priced.

Thanks for reading,

The Watch Professional

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