Oliver has sent in his Speedmaster Reduced, looking a little worse for wear and it’s not running.
I have been waiting a long time to do a Dubois Depraz module, as they have a reputation of being fiddly and parts are hard to find.
The movement is very dirty.
There is a screw that has fallen out of the rotor bridge
I start by taking the auto winder mechanism apart. I also find the rotor bridge screw lodged in the movement.
After removing the screw the movement starts up again.
The watch is fully wound and preforming like a drunken dog, considering it is an ETA 2890.
Here you can see the dial side of the movement and that there is a connecting set of gears that engages with the Dubois Depraz module. The pinion is press fitted onto the forth wheel pivot and is removed very carefully so not to damage the teeth. 
Here I have removed the gear train cock and you can see there is plenty of dirt all over the place.
... and plenty of solidified grease under the barrel bridge.
The old mainspring.
Here you can see the backside of the Dubois Depraz module and it is covered in small fibres and dirt.
I have taken the module out of the case and you can see the dial and hands have received some punishment. I start taking the module apart from the dial side.
I have removed the plate covering the chronograph layer.
There is specs of dirt all over the place as I remove the various components.
Almost taken apart.
I have cleaned the chronograph module and the movement separately so not to complicate things more than necessary.
I start by putting in a new mainspring.
I see that the balance moves freely after oiling the cap jewels.
I put the gear train back in. Everything looks so much better when clean!
I put the setting mechanism back in place.
The movement is preforming much better.
Now for the Dubois Depraz module I will follow a detailed assembly manual provided by Omega.
The parts are clean and ready to be put back together.
Following the manual I put one part in at a time.
Slowly does it.
After a long process it is finally ready for chronograph module covering plate.
Finely the chronograph is back together and the hammer position adjusted.
I put the movement back in the case.
Then I put the auto winder back in place.
I have polished the original crystal and repainted the hands.
Proof is in the pudding when the chronograph is engaged.
A very nice looking chronograph.
I’ve heard that some speedmaster reduced (3150.50) come with a seamaster signed caseback, Is this true?
Never seen one …
hi there overhauling 1 of these movements is the center wheel that driving the chrono module just press fitted on to the pinion ?
thanks chris
watchfix.ie
This is a long-overdue thank you for all your hard work and care Mitka. I’m astonished by the level of service I have received, both this month and when you last had the watch in October last year.
I fully recommend anyone considering sending their watch in to go for it – you won’t be disappointed. Thanks again.
very very good watch with fancy mechanism and great service story. thanx man.
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Wow. I love to come back and have a read through your blog every now and then as love all the detailing and these brilliant quality images. So impressed with your skills as always.
For those of you who have any doubt about Christian’s abilities and swiftness; put them to bed. He is in the middle of restoring my 2890-2 / 1140 Speedmaster Automatic. The watch was sold to me as “restored to factory specifications”. It is anything but. The photo log available to me is fascinating. I find myself shirking all other responsibilities just to study what is happening. He has discovered worn out parts, missing parts, grease and grime, use of glue on O-rings and probably some others. He responds to all my tedious questions and does so in a friendly and professional manner. I couldn’t be happier to have discovered him through this blog.
I can’t wait to see mine Christian!
Dear Christian,
If I leave my 3510 Reduced Speedmaster for a month and then pick it up to wear, I need to swing the watch for a good 5 minutes before it ticks again. After that it works normally. Can you advise me whether this is normal or something is wrong.
Thank you.
Why don’t you just wind it?
Thanks Christian. Will trying winding instead. Didn’t know I could do that.
Excellent work! Too many watchmakers shy away from these chronograph modules and it’s refreshing to see somebody who will grab the bull by its horns!
most watchmakers shy away from dubois depraz modules for good reasons such as non availability of parts and technical documents.Even christen would find it very hard to fix,if there were broken chronograph parts in the module.
I would double Decipher28 on this one. Had problems with similar DDB module myself and no help whatsoever from DDepraz only way to get minimal info is to address to brand Omega in this case. I would appreciate very much if someone share repair manual for this or similar DD module.
I have got the Omega service manual at http://watchguy.co.uk/technical/
Thank you for this – the best pictures by far of a Dubois Depraz module on the web. Can you please say more about why the DD module is so feared? Is it purely non-availability of parts, or are there specific assembly / adjustment pitfalls? I cleaned and lubricated my son’s old Breitling recently which has a DD. I was too scared (after reading about its reputation) for a full disassembly, but managed to successfully clean up the train that transfers the power from the base movement, which was dirty and had brought the power reserve down to 12 hours.
I think there are various reasons. Firstly, it’s an unusual construction, and secondly, parts are hard to find. So it’s easy to get stuck with a disassembled module without a chance of fixing it. So a lot of watchmakers leave it as it is, and live with a reduced amplitude. It is of course also cheaper for the client if the module is left as it is…
If they are clean and we get a good amplitude after servicing the movement, we suggest to clients to leave them, but if the amplitude is too low, we suggest a service.
Oh I have another one of those for you as soon as I can grab a slot!
Wow…46 jewels! Is that just a bit of marketing? Seems a bit overkill.
Looked very daunting but a very nice result.
The jewels are all in the right places, might have been marketed when sold, but no bragging on the dial or case. So all fine in my book;)
well done sir
Well done, Mitka! That’s another big step, and lots of watch repairers shy away from these Dubois Depraz modules. It does take a bit of courage, and you did a great job following the instructions and getting it just right.
Thanks Christian. Helps having a good tutor;)
Great job!
Congratz on your first DD modular movement.
Need to find you another one to service some day:-)
stunning work as per usual. owner must be very happy with that.