Service
Horologism shares a detailed account of servicing an ETA 7750 movement, following up on a previous Grand Seiko project. This post provides valuable insights into the importance of regular watch servicing and highlights a specific issue with the reversing wheel, offering a practical look at watch maintenance.
Well, I'm sure most of us know why that is to begin with, but it doesn't hurt to talk it over once in a while. Watches have very precise movements with tight tolerances, and just like any moving mechanical object, it should have proper lubrication and be free of any debris. Why do you think your car has a few liters of oil and a filter?
Ever since I got this watch it had very hard hand winding. Something I thought to be very strange but never got around to get it looked at since I don't wear it TOO often. 
After the ordeal with the Grand Seiko, I decided to have this one serviced as well, and see if we could figure out what was wrong. I later realized that the watch didn't have the infamous 7750 wobble (well it did have a bit, but not the "normal" obnoxious wobble), something was definitely up!
I took the watch apart (hands, dial, case) and took the movement to Omar (my watchmaker) for service. He disassembled it and inspected it and after taking apart the automatic module found the issue. The reversing wheel only had one side of the axle still whole!. In other words, one side of the axle was there, the other had turned into dust, as you can see below.
On this side, you can see the part of the pivot that was still there 
The other side however is perfectly flat! Where did the rest of it go?!
It turns out this is one of the most stress prone components on this watch, and no lubrication over its life combined with regular use (previous owner) made the pivot turn into dust. This is why the winding was so "gritty"
Thankfully he had the part and was able to swap it out.
As an added bonus, he also had the top half of the reverser, only instead of being a plain "gear" it had two rubies, and was an exact fit, so I had him install it instead of the old gear (as seen to the right of the complete reverser. So now my watch has 27 instead of 25 jewels! The use of these rubies may be unnecessary, but I figured it would be a worthy upgrade since we had the whole thing apart anyway! This was not an aftermarket part, but rather an original ETA part with a better specification!
Here's the end result, you can see the new pivot where it should have been before, as well as the two ruby jewels!
The rest was just the cleaning and assembly of the movement
Here Omar is lining up the parts
All of the parts lined up and ready!
Some parts, close up
Spring Barrel
Main plates, rotor, bridges
The balance bridge and pallet-fork/escapement wheel
Ready to be assembled
Barrel on
More parts
Here Omar is using some Rodico (the green stuff) to clean any debris that might be on
Ohhhh shiny and pretty
Here is the assembly of the calendar parts
And finishing up the chrono works and auto parts
Placement of the balance spring/bridge
And incabloc spring/endstone
Last part!
Back together again!
Now here's the fun part. Since I took the movement by itself, I assembled the rest up at home. Here's what I used. The movement is in the small white box, protected, and the rest of the parts are individually bagged and labeled in the baggies behind the blue air blower.
Chronograph hands, dial are on
The rest of the hands
And the movement cased up again!
I hope you enjoyed the pictorial!
Regards,
Fred Bonatto
Thanks for the pictorial, Fred, great pics. For those of you who enjoyed that, this link: www.eta.ch 7750 / 7750 .html takes you to a semi-interactive teardown, reassembly and function-explanation of the 7750.
. . . a good friend of yours, Fred . . . every time I try to take photos of my watches under reconstruction, all I get is dirty looks and growls ;-). Thanks so much for crafting these tutorials . . . cordially, Art
, but my hands arent steady enough nor my eyes good enough. luckily(very luckily) i've found a new watchmaker as my previous one had a heart attack and had to give up. i'm never going to get the opportunity to see what Fred see's as i have to post my watches off. my new man worked for Omegas UK service department for a number of years and has just done an updated course run by ETA in switzerland so he's pretty well covered for anything i might want sorted. interestingly he said that he was amaze
I purchase the watch pre-owned and the problem was pre-existing. I'm sure it got worse over time, from say, a worn pivot to no pivot at all! I spoke to Omar about this matter (the wear) and he said that due to the way the winding system is designed, the reversing wheel which is constantly spinning, bears quite a bit of torque, both from the rotor, and from the main-spring, He said he's seen wear on this part in the past and that he felt it was quite frequent, but never to this level. His theory
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