Look here why you cannot change date at midnight

[onzenuub 325]

In the 7750 movement (Asian or ETA) the date cannot ne changed around midnight. If you try it (it is not possible) you can damage the movement. This tuto shows easily how this happens.

 

Next video has comments to explain the problem of changing the date at midnight.

 

 

As the video shows:

 

1.- First, the date is changed using the crown. The “double corrector†pushes the date wheel and the date changes.

 

2.- Second, the crown is in the setting time position and the movement is setting forward. We are setting the time, running the hands clockwise. At midnight, the “date indicator driving wheel†will push the date wheel, and date changes.

 

3.- Follows that we try to change the date using the crown, and it is not possible. Because the driving wheel and the date wheel are touching…no movement is possible…change of date is impossible.

 

If we insist, we could produce damage in the movement. Next picture shows the “intermediate setting wheelâ€, without some teeth, for that reason.

 

[dingle 60]

thanks for posting onze.

[AustinTech 0]

+1 - thanks Onze

 

 

I never knew why it didn't work - just that it didn't and that I could damage my watch.

 

Good stuff.

[onzenuub 325]

some clarification:

 

A7750 at 21600 bph have this problem.

A7750 at 28800, it seems modern versions do not have this problem.

Swiss 7750 all has this problem

 

regards,

 

Francisco

[tissotman 0]

this is the same on genuine 7750 watches i have a tissit prs512 chronograpgh and i cannot adjust day date while hands are between 10 and 2

[u4kuna 0]

What an exit that in this respect of the 7750 Asian 28,800 is better than the ETA 7750.

[jeffw69 0]

Thanks Onze!

[The astromaster 0]

Is 9015 the best?

[Dzjnhj 0]

Spammer!!!

Edited November 16, 2020 by rikracy