Repairing when crown does not change day / date (7750)

[Francisco]

This is a Porsche with A7750 movement. The day/date cannot be changed using the crown. However, the change works at midnight, as following videos shows:

Therefore, given the problem that this watch has, there are two possible sources: a keyless work problem or a problem in the piece that pushes the two day/date wheels (double corrector). So we know where to have a look.

The screwed case back is removed:

The movement is removed:

Time to remove hands and dial:

It is very easy to remove the day wheel:

Red arrow in following picture shows the piece that pushes the day/date wheels (double corrector) when the crown is rotated.

As it was said before, this piece is one candidate to be the source of the problem. When I touched it to examine it

[Toadtorrent]

Love it love it love it. Thanks again for some awesome info.

[DuDro]

Great tutorial!

I've experimented on my own to fix a similar problem. Not easy for the untrained or faint of heart...

[Slartibartfast]

Excellent source of information for the brave.

Keep them coming!

[Jkay]

I enjoy these tutorials very much!

[Rolexman]

Here's a problem I once had with the manual date change. Just ading more info to the already great post !