Manual date change on a A7750

[Rolexman]

Yesterday I received my third Skyland with movement issues. This time I can't properly set the date manually. When turning the crown sometimes the DW jumps and sometimes not. This only applies when trying to set the date by hand. In normal 'time-mode' it does jump at midnight as it should. But when I try to set it manually I hear sort of a clicking noise. As if the teeth of the DW don't engage or slip. I did a search but nothing really came up. All I can say is that the 'slippage' doesn't apply to certain dates so it can be excluded that the DW is bend or the dial is touching it.

I'm thinking of removing the dial and hand to take a look at the DW but I have no clue of which part specifically needs attention?

Input is much appreciated.

[RWG Technical]

The manual date change is done with a small gear attached to a plate that engages into the clutch gear. The date change gear assembly is on a pivot and pin and moves from side to side, into the datewheel teeth to change the date, and out of the way so the datewheel can change automatically.

Once the dial and hands are removed, insert the stem, put it in the datechange setting position, turn the crown, and look for the small gear that is on the plate. You will see it move from side to side as you turn the crown CW and CCW.

MAKE sure you remove the stem in the WINDING position only or you will have problems.

There is a defect with many A7750's with this gear and plate, the problem is that it doesn't stay engaged into the clutch gear and wobbles around instead of being firm. You will see a small cover over the datechange gear, remove the one screw for the cover, and remove the cover, and have a look at the gear assembly for any problems.

You can eliminate the keyless works as the problem by simply going to the time setting position, if you can set the time ok and it doesn't slip, the problem is with the actual datechange gear not the keyless works.

Fixing it can be many things, it all depends on the actual problem, which is why you have to inspect and investigate and discover what is happening, and then figure out how to fix it.

RG

[andreww]

Also, to state the obvious, you are not trying to set the date while the time is between 10p.m. and 2a.m. are you?

[Rolexman]

The manual date change is done with a small gear attached to a plate that engages into the clutch gear. The date change gear assembly is on a pivot and pin and moves from side to side, into the datewheel teeth to change the date, and out of the way so the datewheel can change automatically.

Once the dial and hands are removed, insert the stem, put it in the datechange setting position, turn the crown, and look for the small gear that is on the plate. You will see it move from side to side as you turn the crown CW and CCW.

MAKE sure you remove the stem in the WINDING position only or you will have problems.

There is a defect with many A7750's with this gear and plate, the problem is that it doesn't stay engaged into the clutch gear and wobbles around instead of being firm. You will see a small cover over the datechange gear, remove the one screw for the cover, and remove the cover, and have a look at the gear assembly for any problems.

You can eliminate the keyless works as the problem by simply going to the time setting position, if you can set the time ok and it doesn't slip, the problem is with the actual datechange gear not the keyless works.

Fixing it can be many things, it all depends on the actual problem, which is why you have to inspect and investigate and discover what is happening, and then figure out how to fix it.

RG

Thanks Rob! As per your description the keyless works can also be excluded as the problem. I will investigate the datechange gear and look what is going on. What can be done about the wobble if that's the case? Is there a remmedie?

Also, to state the obvious, you are not trying to set the date while the time is between 10p.m. and 2a.m. are you?

Nope

[RWG Technical]

Thanks Rob! As per your description the keyless works can also be excluded as the problem. I will investigate the datechange gear and look what is going on. What can be done about the wobble if that's the case? Is there a remmedie?

Normally if the plate with the gear on it is too loose, meaning that there is too much of a gap between the datechange plate and the cover that holds in in place, I replace the cover with a spare one to see if this fixes it.

It will be more clear to you when you open it up and have a look.

Sometimes the datechange gear can also be loose, you will be able to see this when you test it.

Also, you can have the datewheel sitting too high and not engaging to the gear teeth correctly. The reason for this is the datechange cover plate is not pressing down far enough to hold the datewheel against the movement. The fix for this is to try and bend the cover edge over the datewheel teeth down so it holds it down.

As soon as you take it apart and test it, the actual problem will be visible and then we can take steps to fix it...

RG

[Rolexman]

Normally if the plate with the gear on it is too loose, meaning that there is too much of a gap between the datechange plate and the cover that holds in in place, I replace the cover with a spare one to see if this fixes it.

It will be more clear to you when you open it up and have a look.

Sometimes the datechange gear can also be loose, you will be able to see this when you test it.

Also, you can have the datewheel sitting too high and not engaging to the gear teeth correctly. The reason for this is the datechange cover plate is not pressing down far enough to hold the datewheel against the movement. The fix for this is to try and bend the cover edge over the datewheel teeth down so it holds it down.

As soon as you take it apart and test it, the actual problem will be visible and then we can take steps to fix it...

RG

Okay, very clear. Will do some disassembling over the week-end and will post an update ASAP. IMO you deserve a paid section on this board. Your info is of great value and I would happily pay for it (maybe you should discuss it with Admin ). Can't express my graditute enough for your extensive and helpfull answer!

[Rolexman]

You were right Rob (as always )

The pivot and pin(?) didn't stay in place so I bend the plate covering the date gear a bit so that it keeps the date change gear in place.

The arrow indicates the place were the plate came lose from the pivot (due to the little pressure form the cover plate)

This made the date change gear slip over the DW teeth

This is the part of the cover plate that needed to be bend downwards.

Thanks a Million Rob! You saved the day (date ).

Greetzzzzz,

Mark

[RWG Technical]

I knew you would figure it out and fix it, congratulations excellent job!

RG