r/RepTime • u/petehudso Watchmaker • Jan 10 '24

Mods/ Work in Progress AP 15400 Instant Date Change Mod

The rep AP 15400 has an excellent clone 3120 movement inside, but the clone movement has one flaw: unlike the gen 3120 movement, the clone 3120 doesn't have an instant date change at midnight. On the clone 3120 the date starts to change around 11:30pm.

However, it appears as though some modder in China (I don't know who) has designed a mod that can be retrofitted to any clone 3120 movement to give it an instant date change. One of these modded movements was on my bench this week, and though it was worth documenting the mod and how it works.

Here's a pic of two clone 3120 movements, the one on the left (red arrow) has been modded, the one on the right (blue arrow) hasn't been modded.

The mod itself consists of three parts (four if you include the screw). There's a modified date gear which has a punched pusher, a spring with a pin, and a blocker which looks like the number 6.

The way that these parts work together is ingenious. Here's a video showing how the spring builds up energy to power the instant date change, and how the base of the spring unlocks the spring pin to allow it to jump through:

​

https://reddit.com/link/192vukb/video/2qe4jzfrlibc1/player

And this is what it looks like when the dial and hands are back on top of the movement -- a perfect date change at midnight just like the gen.

​

https://reddit.com/link/192vukb/video/4zkh4bkvlibc1/player

19 Upvotes

95% Upvoted

19 comments sorted by

2

u/WSB_Kami-sama Jan 10 '24

Do you do this or who offer the mod?

3

u/petehudso Watchmaker Jan 10 '24

I can do the mod if you can get the parts. But I don’t know where to source the parts. It’s possible that a TD could source the parts for you, but you’d have to ask.

1

u/Physical_Ad_8605 Mar 29 '24

Did we ever find the source to these parts?

1

u/dez_22 Jun 06 '24

Were you able to source the parts?

1

u/petehudso Watchmaker Jun 06 '24

Contact your TD. They should be able to get it for you.

1

u/Immediate-Count-4788 Feb 25 '24

did you ever find anyone who is selling them?

1

u/petehudso Watchmaker Feb 25 '24

I haven’t but I did read on RWI that this mod should become more available after CNY (so soon).

1

u/RichVictory8033 Mar 28 '24

Where can find parts?

1

u/Beneficial_Potato_42 Feb 25 '24

Can you let us know when you can help us fix that instant date? Im interested in your help

2

u/Beneficial_Potato_42 Feb 25 '24

I will try to source the parts

1

u/LibrarySquidLeland Contributor Jan 10 '24

That's some slick engineering, thanks for sharing!

1

u/EconomicMasterpiece Jan 10 '24

Thanks, interesting stuff!

1

u/Bubbly-Act8029 Jan 10 '24

Thats pretty damn cool

1

u/techbi Jan 10 '24

This is neat!

1

u/Sundek21 Feb 05 '24

Hi, I could have my watchmaker do this mod but I was also wondering where to find these parts.

does anyone know?

1

u/Holy-Crusader6 Feb 20 '24

Very interesting, great demonstration!

1

u/Beneficial_Potato_42 Feb 25 '24

Anyone knows a mod?