Valjoux 72 chrono hands moving

[watchfellow]

Hi everyone,

I just recently put back together a Valjoux 72, and the chrono start, stop and reset function work well. However, while the chrono is stopped, and the watch is being worn (ie being moved around on the wrist) the chrono hands move slightly. It doesn't have this issue when the watch is resting on my bench. Usually the minute and hour counter hands move, while the seconds hand does not. However, the last time I tried to wear the watch, I found all 3 chrono hands to have moved some. Sometimes by a few degrees, sometimes a little more. I don't think the hands are slipping because they always reset back to the same spot. Can anyone guide me or suggest where I can look to begin to remedy this issue? Thank you in advance.

IMG_2753.HEIC

[Tudor]

I am no chronograph expert, but I’d look at the way the reset levers are pressing on the hearts. 
 

On Omega movements there are eccentric screws as well as the retaining screws, and those manuals always say not to mess with the eccentric ones. 
 

I might be way off base but that’s all I can offer. 

[HSL]

Unfortunately, I don’t have a proper browser for this file format, would be easier if you posted in PNG or something like it. But one at least can see something.

I’m not sure if this is a 72 by the looks of some parts on the chronograph side. Might be a later one (Valjoux 724).

I would say the minute register pawl (minute recording jumper) isn’t in the correct position, it looks like it is stuck under what would be the flyback lever spring (hammer spring). If the flyback spring (hammer spring) is pressing on the flyback lever (hammer) the zeroing of the chronograph second will not be able to hold the seconds wheel (chronograph runner) in place, it would just like you describe move when subjected to small vibrations or other subtle forces. So, one would wonder if it just works but not completely correctly.
When put in zero position the flyback lever (hammer) will hold it firmly in place wtih the help of the flyback lever spring (hammer spring)  if it works correct.

Edited October 10, 2020 by HSL

[watchfellow]

Thank you both for the replies.

HSL you are brilliant. I adjusted the hammer spring and it indeed works correctly now. The recorder hands do not move when the chrono is disengaged. Thank you very much for the help.

And I apologize for the format of the photo.. I just realized my iPhone is taking photos with this strange new format.. I could have sworn it used to take photos in jpegs!