Seiko 6119c won't start after service

[Gaus]

Hello guys, I have serviced a seiko 6119c. All the wheels and the balance moves free, but the watch won't start. If I help the mainspringbarrel, the watch runs. Is this a mainspring issue? 

Thank you all in advance. 

[jdm]

Just now, Gaus said:

 Is this a mainspring issue? 

That seems a very hurried conjecture to me.
There is a sequence of steps which help in determining why a watch doesn't run, do you know or have followed the standard diagnostic list?
In all cases I'm sure that someone will post it here once again.

[watchweasol]

Hi sounds like a total power loss, 1, remove all power from the mainspring. 2 remove balance . 3 remove pallet/fork,  4 put two turns on the main spring, 5 does the train run down with a little reverse spin.  If not you have a train fault ie bent or broken tooth dirt in the train broken pivot etc so investigate, if all is ok re insert the pallet/fork and apply power. does the pallet/fork snap back and forth when moved. if not go back to square one and re investigate.  You must achieve the sharp movement in the pallet other wise it will not impart the power to keep the balance oscillating. 

[Gaus]

Thank you very much. I will investigate further. With kind regards, Hans

[JohnR725]

1 hour ago, Gaus said:

Is this a mainspring issue

 

1 hour ago, watchweasol said:

remove all power from the mainspring

when you manually wind the Seiko watch and yes you can do that by winding the ratchet wheel does it feel like you're actually winding a mainspring? Or when  following the suggestion above is there any power on the mainspring at all to letdown? Plus when you're servicing the watch did you take the mainspring out of the barrel.

[Gaus]

Hello John, yes I did manually winding the mainspring, and that felt well. And when I remove the balance and the pallets, the wheels run free. So that seems to be okay. But there is no sharp movement in de pallets, as Watchweasol asked. 

[clockboy]

The first check IMO is to remove the balance and check to see if the pallet folk has any power to it. The escape wheel should sharply move on a tooth when the pallet folk is moved. 

[Nucejoe]

Is there any end shake on the fork arbour?  loosen the fork ridge screw then do the nudge test.

Regs

[watchweasol]

If the train is free but there is no movement in the pallet/fork, as Joe says check the end shake and closely inspect the pivots and jewels of the cock fir chips/cracks and bent pivots.  Fit just the pallet/fork and the balance then oscillate the balance manually, if all is free it will oscillate for a time on its own quite happily for a short while if only a turn or two you have a fault in the pallet/fork area.