7750 Concern - Your Thoughts?

[rikhek]

A7750 Doing Something Strange - Your Thoughts?

Just took delivery of a HF Blacksteel Skyland Avenger with the A7750. Observed something that concerns me.

The chrono second hand "jumps" like it's missing a beat at the 58 second mark every rotation in concert with the chrono minute counter at 12 advancing a minute. FWIW, this is a seconds at 9 watch.

I checked my other A7750 watches and none of them exhibit this behavior. Does this indicate there's a mechanical issue with the movement?

Thanks in advance.

Rick

P.S. I'm already aware the "best" way to treat an A7750 is to use the chrono sparingly...

 

[WatchFnatic]

Correction , dont use the chronos

 

[rikhek]

Hoping someone can share their knowledge specific to the question asked?

 

[numero2]

Maybe yes, with the oscillating pinion or maybe it's only the second chrono hand that touch the crystal. To know, just put the movement out of the case and run the chrono. Ih it runs well, it touch.

 

[Ko67]

Thant is likely an adjustment issue on the jumper that keeps the minute recording wheel in place. The jumper is putting too much resistance in the minute recording wheel and it makes the chrono driver stutter on first contact That can be adjusted in gen ETA movements but it is precisely the kind of issue that a7750 movements have. The eccentric screws that make those adjustments suck on s7750's and are impossible to use . Someone could perhaps try to make the adjustment to lessen the tension but as a watchmaker I have learned that there is an equal chance of disaster and success each time you touch a tool to an a7750.