Another day, another chronograph 😉 After the Kelek, it’s time for something more mainstream, a Breitling Chronomat. When it comes to the movement, the ETA (Valjoux) 7750, it doesn’t get more mainstream than that. This is the movement that is the most used in chronographs, and the one copied in China and ticking happily in all the fakes out there. And there is a good reason for that – it’s a good workhorse, beating at 28,800 bph.
Dear oh dear – it’s high time for a service!
First look at the ETA7750.
Before I remove the movement from the case, I take the rotor off.
With the movement out, the dial and hands come off next.
The bottom plate with date ring. The provision for a day ring is there as well, as you can have the 7750 as a day/date as well.
I start off with the top plate.
The chronograph layer becomes visible. The auto winder on the 7750 only works in one direction, and the little ratchet wheel (brass colour) is visible. Once thing I don’t like about the 7750 is the click spring for the auto winder ratchet wheel (and the one for the click wheel on the barrel). They are super-cheap wire springs fixed on to the plate. But that’s just an aesthetic consideration.
Most of the chronograph bits are gone, and you can see the barrel wheel.
The chronograph plate.
The gear train.
The old mainspring. As new ones are readily available, I will of course replace it.
Time for the bottom plate.
Below the date wheel, another plate sits on top of some other chronograph gears and the keyless works.
And here they are.
And ready for the cleaning machine.
The clean parts ready for reassembly.
Escape wheel, pallet fork and cap jewels after the epilame treatment.
With the new mainspring on the right, it’s time to get stuck in!
I start off with the mainspring.
Then the balance jewels go back in.
The gear train in place.
And the wheel bridge / chronograph bridge back in place.
I will put together the basic movement first, to make sure everything is working as it should, before reassembling the rest.
Here we are, ticking again.
Oh yes, that looks so much better!
In this photo, you can see the click spring blocking the click wheel. Worthy of a £5 Chinese movement, but a construction like this shouldn’t feature in a Swiss movement of this price range. It works, but it’s ugly.
All chronograph bits back in place.
Nice and clean.
Now I turn the movement over, and start on the bottom plate. The hammer for the hour totalizer is a blighter to put in – check out the assembly at the top at 12 o’clock – how the wire spring has to go over two parts. Very very tricky to put in without it flying all over the workshop.
All is safe under the plate now.
And the date wheel is back in place.
The dial and hands go back on.
And I can case the movement again.
Charles from WatchGlassCutting polished the case for me, and he did a great job.
Back in the case, with a new gasket.
Case back on.
Time for the waterproof testing – pass at the first try.And we are back in business!