7734 dropped...

[Tudor]

I have a Chrono running a 7734 (2-register, 45 minute counter, date at 6) and I dropped it in the bathroom. 

I cracked it open and the balance is fine. Moves easily one way but is clearly stuck the other way. Running seconds gear seems free, but restricted due to pallet fork being bound up. 

I think the fork is out of whack with the driving pin on the balance. Maybe over rotated and the pin in against the fork, rather than between the tines. 

I’m not good enough to tear down a 7734 (well, AND get it all back together) so is there a manipulation I can attempt to get things back in place? Maybe let down the spring and then try to move the fork while keeping the balance out of the way?

interested to hear the responses. 

[RyMoeller]

You should be able to remove the balance without getting into any of the chronograph bits.  That will allow you the freedom to examine both the pallet and the impulse pin on the balance wheel.

[oldhippy]

From your description it might be over banked. That is where the impulse pin is one side of the pallet fork. Unscrew the balance, insert it, in its correct place, and see if it works.

[Nucejoe]

If you are good at dropping things , you can  partially loosen the balance bridge scerw ( not remove the bridge/ balance)  lift the bridge about three millimeters to allow for lifting the ballance wheel, get the impulse jewel in place between the tines, tighten the screw back. 

 

 

[Tudor]

Good suggestions. Thank you all. 

I am concerned as one of the gears (I assume for Chrono due to location) overlaps the balance wheel. I don’t know if I have three mm to play with there... but if I can get the balance clear of the bottom jewel I can take it out of the way. I’m just not 100% on that. 

I have set it aside while I goof around with the fake Rolex 3135.