Zenith movement 16520 and 16523 hacking seconds

[aalkazemi1990]

I own a 16520 and recently purchased a 16523. As far as I know they should have the exact same movement. Neither have hacking seconds. On the 16520, when I adjust the time backwards, the seconds hand pauses then goes backwards. On the 16523, the seconds hand just keeps moving correctly even if I set the time backwards. What could explain that? I got both watches from very reputable dealers (AVW and Keystone). The 16520 is an N serial model and the 16523 is S serial.

[fmc000]

The behavior of my former N-serial 16523 was exactly like your N-serial 16520.

[Arnozerosix]

I am not a tech expert, but if i am not wrong the hacking second is a fonction of the movement.
Of course both of your babies should work exactly the same, except if the hacking fonction of your 16523 is not working. Your horologist should be able to fix it with a quick service of the caliber....
This happened to me on one of mine and it was fix with a 50$ service.

[fmc000]

Originally Posted by Arnozerosix

I am not a tech expert, but if i am not wrong the hacking second is a fonction of the movement.
Of course both of your babies should work exactly the same, except if the hacking fonction of your 16523 is not working. Your horologist should be able to fix it with a quick service of the caliber....
This happened to me on one of mine and it was fix with a 50$ service.

There's no hacking function in the Rolex 4030 movement (AKA Zenith El Primero).

[Arnozerosix]

Originally Posted by fmc000

There's no hacking function in the Rolex 4030 movement (AKA Zenith El Primero).

i trust you, but i never said there was a hacking, i just mentioned that hacking was a fonction* of a movement ;-)

*at least what my horologist explained me ...

[mikeo1]

The momentary backward movement of the sweep second had is related to the tightness (slippage) of the cannon pinion; backwards one is a bit tight or not as well lubed -- not a big deal

[GTS Dean]

My '98 16520 has stopped/backed-up the seconds hand since brand new. I actually prefer this feature which allows fairly precise time setting with varying back-tension on the crown in the #1 position.