Double digit calendar alingment

[Logixa]

So I received this watch 2 days ago from the owner, saying that another watchmaker had serviced it but the the double digit date alingment is off. It goes from 14 to 24 and much more. So other than the 1 to 19, everything is jumping off. To me it sounded like that the date discs are not aligned correctly after the servicing.

So I opened it up and found 2 wheels with a hole in them, of which the left wheel has several bigger gear teeth (this moves the left datewheel to the numbers 10-20-30). But I just cant seem to align them properly to make the dates jump correctly. 

How do i properly align the wheels on this? I seem to manage to make the left wheel work properly but the date jumps from 29 to 30 to 31 to 02. It should stay on 1 I assume.

Its a seagull 7750 based movement.

 

 

[nickelsilver]

Looking at the pic, it looks that the right disc has had the teeth modified at the "1", it would make sense that just the "1"is modded, but it looks like two have been reduced in height. I suspect that the "2" functions as normal, but the "1" doesn't advance the numeral disc. So:

From 31, left disc advances to 0, right disc doesn't advance (still 1)- though the wheel has moved one tooth. Right disc advances each day from there, on the 5th the left disc goes to the second 0, on the tenth the left disc goes to 1, right disc is on 0. From "19" left disc moves to "2", right to "0". Same from 29 to 30. Then 31, then left disc moves to 0, right doesn't and again and again.

It looks like the left wheel is on what should be 31, so 3 on that disc. The right wheel should be positioned so that the "31"tooth has just caused the disc to jump. You'll need to double check where the teeth lie after making a jump, but it makes sense that it would be just after they pass the centerline from wheel to disc.

It probably seems silly or illogical that they have two zeros on the left disc, but it allows using the same number of digits per disc, with the same size and spacing, with two identical count wheels to do the movement.

Edited July 31, 2019 by nickelsilver

[Logixa]

@nickelsilver Thank you mate! This is very helpfull and helps me understand it a lot better now!

 

I'll try it out tonight and update this post. Again, a lot of thanks!

[nickelsilver]

There's an alignment mark on the right wheel, I think it should be positioned like in the pic for the date set at 31.

[Logixa]

You were right mate! It's fixed now by the 31th teeth alignment method of you. Thanks again, you sir are amazing!

[nickelsilver]

8 minutes ago, Logixa said:

You were right mate! It's fixed now by the 31th teeth alignment method of you. Thanks again, you sir are amazing!

Ha, I'm glad it worked! I had an El Primero with big date (Chronomaster Open), 3 stacked discs with stars and jumpers all stacked all over, spent a couple hours working out the order. Told customer not to set hands backwards after midnight... (he had done it before, which broke a pin in the system and desynchronized the numbers...), of course a few weeks later he did it again. Luckily I wrote down the sequence.

[Logixa]

What the hell haha that looks like rocket science